 Hello everybody. I think we're ready to start today's webinar, the 24th webinar of the series of Latin American webinars. My name is Alejandro de la Puente. I'm currently a post-doctor fellow at Carlton University in Ottawa and I'll be hosting today's webinar for you. I'm very happy to announce that we're going to be talking about something that I'm really excited to hear about because I haven't heard much about it and it's about the inner 300th parsec of the Galactic Center, as seen by Hess. We're followed live by colleagues from around the world, people in Spain, people in Brazil, Sweden, Chile and obviously France. And before we start the talk by Emmanuel, who I'm going to introduce in just one minute, I'd like to remind you that after the talk, or during the talk, you can put your questions on the questions and answers that are in the Google Plus section of this webinar. And also you can use Twitter using the hashtag low law physics. And we also have now a web page, a WordPress page, where you can follow us online and all the activities that we're actually doing. So today's speaker is Emmanuel Mulan. He's currently a staff researcher at CEA SACLE in France. He received his PhD from LPSC in Grenoble, France and did a two-year postdoc at CEA SACLE before taking on his new position as a staff researcher. The title of his talk is the inner 300th parsec of the Galactic Center, as seen by the Hess collaboration. So with that, I'm going to hand you over to the speaker and I really, really, really hope you all enjoy today's talk and please don't forget to ask your questions right afterwards. Thank you, Emmanuel, and here it is for you to start. Okay, so let me first thank the organizers and I'm very happy to present you what you can see of the inner 300th parsec of the Galactic Center with TV gamma rays with the Hess observatory. Okay, so you can hear me well? Yeah, everything is actually very, it's perfect. Okay, so today's, so this Galactic Center region has been observed routinely for more than 10 years with Hess in the, for many aspects and there are many science cases we can cover with these observations and today I'm going to talk about the quest for cosmic origin with these observations. Okay, so let me first recap a few things as in a short introduction so all of us know, all of you, know that we are continuously bombarding by cosmic rays on Earth and they are mainly composed of, at about 90% of protons. This is the main components of the cosmic rays arriving on Earth. Okay, so these protons, they are trajectories deviated by magnitude fields in the interstellar magnetic field and also of course the intergalactic magnetic fields. So what is interesting is that this flux of cosmic rays is measured over more than 10 order of magnitude in energies and more than, yeah, many order of, ordering flux. What we can see is that we have almost a power low extended over many, many order of magnitude and we have basically two, two regions in this spectrum, the low energy parts. It is basically a cosmic rays of galactic origins and the low energy coming to the GV at least, they are produced by the supernova remnants. On the far hand of this cosmic ray spectrum, we, it is commonly believed that this cosmic rays have an extragalactic origin, but in between, the origin is not clear and this is, let's say, between a few, 10 to the 15 electron volts, 1 PV up to 100 of PV. So this region is called the knee and for this region, we need to postulate or at least we need other galactic sources, or population of sources to provide the required cosmic ray flux we observe. And this kind of sources, we call pavatrons in the sense that these sources accelerate cosmic rays up to PV energies at least. Okay, so proton, of course, they are accelerated at the sources, but deflected during the, their way up to the herd. What is interesting is that the gamma rays can be continuously produced at or in the vicinity of the sources by both during proton interaction or propagation. And these gamma rays, at least at the galactic scales, are not deflected and then they propagate up to the earth as in straight lines. So in that sense, we can, they point back to their source. This is the one main point and with this detection of very high energy gamma rays, we can add the morphology of the gamma rays at the projection site. And these are useful, very useful probes to look for the accelerative particle of the sources. Okay, so just in one sentence, what is interesting is that these gamma rays, they are very effectively produced through electromagnetic or electronic, electronic or electronic interactions. And what is interesting there is that they can be effectively detected in the detectors by spaced or ground-based instruments. Of course, they also effectively interact with matter or radiation or B-fields during their travel up to the, up to the earth. So even the information is, they contain very important information about the acceleration processes, but they can arrive to us with some distortion. So to track these sources of PV cosmic rays, these pair of atoms, they are basically three main channels. We need, of course, gamma rays in the 10,000 TV energy range. Also, neutrinos are effectively produced in case of proton interactions. So they travel directly unaffected up to the earth. So they are very useful probes. And there are some secondaries, I would say x-rays produced by secondary electrons during proton interactions. And these x-rays can carry out significant information also to PV cosmic rays. So for the detection, so the gamma rays, they are, we all know that they are detected with kilometer square array, which is the ground-based chunk of rays. The neutrinos, they are detectable by, with some difficulties, but they are detectable with ice cube and, or kind-free nets. And they carry also unambiguous signatures. And we have also, as I said, the x-rays that are produced by the secondary electrons. And in case of very high magnetic fields, these x-rays are produced simultaneously to the gamma rays because of the very strong synchrotron losses in case of very high energy environment, which is the case of the galactic center. So they are produced, basically, seamlessly to the gamma rays. Okay, so in order to track to four pavatrons, cosmic ray pavatrons, with the gamma ray measurements, we need to demonstrate that these gamma rays are produced through adenic interactions. And that the parent proton spectrum can extend at least to one pv in energy. So, but what we can see is that these protons, to allow for the gamma ray observations, we need targets for these very high energy protons. So this target can be matter, rejection field, or magnetic field. So a target is required for the production of gamma rays. So one interesting target is the gas clouds that are, let's say, we can coordinate like barometers of cosmic rays. So these gas clouds are very useful in that case. And one thing which is important is that the gamma rays emissions coincide with the target material, the gas, but not necessarily with the primary particle accelerators. So in that case of proton-proton interactions, the kinematics of the process of the inelastic scattering of energy protons in the gas, in delta slash gas, tells you that the gamma rays is about one-tenth of the proton interactions. So what we need to detect in gamma rays is gamma ray energy up to about n dot tv. Okay, so what I just said can be, is presented in this sketch. So what we can see is that protons are accelerators and can diffuse in the vicinity of the source. And in the case they eat gas, they can produce gamma rays and neutrinos that travel directly to the Earth. So this is an example of the spectrum of the broadband energy spectrum we can expect. So you can see the gamma rays, the neutrinos, and the x-rays I just talked about at much lower energies. Okay, so now just a few slides about the detection techniques. So these gamma rays produced as they enter in the Earth atmosphere, they interact very efficiently and they produce an electromagnetic cascade and charge particle in the, in the shower, produce a chain of light and this chain of photons can be collected on mirrors. The light pool of the chain of light is about 100 meters and radius on the ground. So if you pave the ground with a chain of heliscope, you can collect and even have multiple images of this shower in your, in your telescope. So the chain of light is focused on the cameras that are the focal plane of the mirrors and this last light flash is very short in a pixel basically, in a pixel of camera with about a point one degree field of view, the light flash lasts about 10 nanoseconds. Okay, so of course there are many, the gamma ray showers are dominated by the number of adren showers and just give you a sketch of what the gamma rays and the proton shower look like and what we can see is that here the gamma ray shower is much more concentrated along the longitudinal, along the longitudinal axis and the proton is much more spread on the lateral axis. This is due to inelastic interactions and IPG particles are produced in this kind of shower and this creates sub-electromagnetic showers. So this is what you can see for instance for these two showers in the interacode flight on the ground. What you can see is that for the gamma rays you have more or less a light pool, a circular light pool, in case of protons you can see many shower showers on the ground. Okay, in the camera what it looks like, so you have the adren light even so given the multiple sub-shower you have different clamps in the cameras. For the gamma light we have a kind of ellipsis topology in the camera, in the camera. Muons that are also copiously produced from adrens or interaction gives you circles so they can be easily identified. So the discrimination at the first, at the camera level is done in the shower image in the camera on the topologies, you can calculate moments of the image in the camera for instance and if you have a multiple image of the same shower in different camera it helps you a lot to discriminate against background and also to improve the reconstruction of the particle direction. So in that case what you can do is that you can compare your recorded image to a database of image and through a maximum likelihood procedure you can recover the best parameter of any showers, energy direction, impact parameters and so on. So on the analysis level you can make a cut to separate your sample into gamma light even and adren light even. Of course what you can see on this slide on the plot you can see that you have still some contamination of background even in the signal sample. So to fight against or to remove this residual background you have, there are several techniques but one is to use the on minus off type measurements. So in this case assuming that the residual background is uniform you measure the background symmetrically in the camera field of view to the center of the camera. So in that case you can estimate the residual background which is in the on region from measurement in the off region. Of course you can use large off region to have a very good measurements and reduce statistical uncertainty on this background level. Of course it can work only if the signal region is lower in scale than the field of view of the camera for any extended emission which is at the left of the size of the camera field of view. This kind of measurement doesn't work and it automatically subtracts any extended emission. Okay so now the S experiment is using this technique and it works well since more than 10 years now and the S experiment is you may know located in Namibia and it consists of two phase. The phase one is composed of four telescopes of 12 meter in diameter with field of view of 5 degrees and eye granularity camera with more than 900 photometrificators and the energy threshold for any angle observation is about 100 GV. The angular resolution pair of camera rays is better than 0.1 degree. Energy resolution is about 15 percent. It works fine since 2003 and since 2012 one additional telescope is present at the center of the array. This is a big telescope of 20 meter in diameter, a field of view of 3.5 and a camera of more than 2,000 photometrificators. It aims to reduce the energy threshold down to several tens of GV at the price of degraded angular resolution about 0.4 degree at 40 GV and works since 2012. In parallel to that they are also the upgrade of the S1 camera but what I will present in the following would be only result from the phase one of S meaning only data taken with the 412 meter telescope. Okay so we are detecting many sources in gamma rays and what we call teratron since the gamma rays are produced up to TV energies and so far we have more than 170 gamma rays sources detected between 50 GV up to 80 GV and with each source is a particle accelerator. So this is a number of sources you can see that it increased quite a lot and since 2005. So there are many kind many accelerators with related to many different sources. First we enable starbursts, AGM, etc. One thing which is important with S and it is a big contribution of the experiment is a scan of the galactic plane and about 77 sources have been detected in the galactic plane surveys with S in the beginning. Okay but about the pavatrons so far there is no pavatrons even what we think to be the main supplier of pavatrons, the supernova remnants. All the supernova remnants we detect so far with ground based telescope does not have the required features to account to be robust pavatrons. For instance the well known supernova remnants ROG-7013 is a very bright super supernova remnants but has a cutoff at TV energies or so. So it cannot accelerate efficiently up to up to PV, the protons up to PV energy since the cutoff in gamma rays has about a few TV. Okay so the galactic center region is very interesting for us since we can see this region a large amount of hours during the years under low zenith angle. So it is very good for the energy threshold and the sensitivity but this region is very prior to it as you may know so there are many sources, SNRs, Prisawin Nebulae and for instance the in the radio map you can see here there are many structures you can see for instance some supernova remnants of molecular cloud you can see and even some arc feature. Okay one important thing is that region and is that it contains giant molecular clouds which is called the central molecular zone and this is massive structures we reach very rich in gas and this is about 10% of all the gas in the galaxy so it's a huge concentration of gas in that region. Okay so it's a very effective target for protons for instance. Okay so the galactic center seen by Hess in 2005 you have two bright point like sources you may not heard of so the central emission is SG 1745 minus 290 so this source is still unidentified so we don't know exactly which is the counter parts of these emissions and we have the G09 that have been detected also. Further observation of these central emissions of G714 revealed ion energy cut off in this on the spectrum which is preferred about power low by significantly preferable power low and the cut off is at about 15 TV so it is a strong emission about 10% of cloud flux point like and so far we did not detect any variability the flux is about constant we detect about 1 gamma per minute. So about the position of these sources with the precision measurements we can see that now we are able to exclude some counter parts in the vicinity within the 10 portions and for instance the supernova remnant is excluded at more than 5 sigma and the counter parts that are the viable counter parts are the supermassive black hole, the P-wing which is marked with the black triangle and also a spike of dark matter. So subtracting these two point like emission what we detected in 2005 is a diffuse emission which is partially correlated to the distribution of the density of molecular gas of the central molecular zone and this points toward an anodic origin of this emission I will see. So now more than 5 years later we have much more statistics in these regions the previous map was done with about 50 hours now we have much more than that we have more than 200 hours of exposure on Sagittarius A star and we can do very detailed and spatial measurements of the diffuse emission. So this is the actual map the access map and below this you can see the angular distribution from Sagittarius A star of the emission. So in the map in slide 31 the data set we have with S it is more than 100,000 gammas in this map and this is the deepest exposure we have in S and we can do very detailed map of the emission. So we have a complex structure of the emissions as we can see and if we zoom in this is the map we had in these years and you can see the diffuse emission in Galactic coordinates and so Sagittarius A star is marked with a star and you can see in red the diffuse emission which is extended and correlated to the molecular cloud distribution this molecular cloud distribution is represented by the white contours that give you the density of clouds basically. So what we did is that we measured the gamma luminosity in different regions that are the annulite and the circular region black region and we use the measurement of the cloud mass that are done independently and with this two quantity we can go back to the cosmic ray energy density since basically this is proportional to the gamma luminosity of other mass. So what we do is that we measure the flux of gamma rays in each of the regions and compute the luminosities and given the mass measurements in each of the regions we can compute the cosmic ray density. So for instance in the slice of the three we can compute the cosmic ray density in the first open annulite and we can do these measurements in all the black regions where we integrate the signal and what we can see is that the cosmic ray density we can measure is decreasing as we go further to the center of our galaxy. So this is what we can see here and what we have is that we have a decrease of the cosmic ray density that allows for the earth to locate the accelerators of the protons and from the measurements what we can see is that the 1 over 4 behavior is prepared by the data and significantly prefer over a flat behavior of the cosmic ray density or even 1 over r squared dependency of the cosmic ray density. So there are two conclusions that first we can locate the accelerators, it is located within the 10-portsec of the galactic center and given the dependencies of the cosmic ray density we can say that we have a continuous injection of protons with diffusive propagation on this scale. In order to fill all this central molecular zone the injection must be continuous over more than 10 to 1000 years or so. Okay, so now we can also do some detail spectral measurements and on slide 43 on the right panel of the figures on the top you can see an open ring and we extract the gamma rays flux from this region and this is what is presented in the lower left panel, this is a flux of gamma rays as a function of energy and the spectrum of this region is given by the red points and what we can see is that the flux of gamma rays is a pure polo and there is no sign of or hints of cutoff in the spectrum and this is contrary to what we detect in the central emission where we clearly see a significant cutoff. So with the measure flux of the diffuser emission which is the red points we have a pure polo with an index of 2.3 and no cutoff up to about 50 TVs. So with this, this requires that the pure parent proton spectrum should at least expand up to PV energies and given the quality of the measurements of the spectrum, the gamma ray spectrum we can look for energy cutoff in the parent proton spectrums and in which sense we are looking at which energies the resulting gamma ray spectrum is deviating from the measurements and this is what we can see. So we can put some lower limit at various confidence level on the possible cutoff in the parent proton spectrum and you can see for instance that at 68% confidence level, the cutoff in the parent proton spectrum is 2.8 PV. At 90% confidence level it's about 0.5 PV. Okay, so given that spectrum what we can say is that we have some continuous injection over more than 50% of the spectrum in 10 to 53 years and if we calculate the cosmic ray power it is about of 10 to the 38 error per second. So given these two things which is new is that and compared to the 2006 results where we saw an excess of cosmic ray compared to the local C of cosmic ray we detect in the solar neighborhood is that we can now locate the accelerators. It is located in the 10% of the galactic center. What we can say now is that it accelerates protons up to PV energies and the acceleration is continuous given that we can now sample the cosmic ray density in the 200 parsec of the galactic center. So given that we have a robust detection of the cosmic ray atoms. Okay, so but what are the possible counterparts of these accelerators? So of course one of the viable counterparts is the black hole located at the heart of our galaxy and in that case we can see that a significant given the acceleration power of the actual acceleration power of Sagittarius ASTOR and given the rate which is released in acceleration of high energy particles. We have a significant fraction of this acceleration power which is released in actualization of high energy particles. So this is an important point and also what we can say is what we can speculate is that Sagittarius ASTOR may have been more active in the past and we have some insight about this. For instance if it is, we can see that there are, if the Fermi bubbles are connected to some outflows it means that we may have on longer timescales Sagittarius ASTOR may have been much more active and in that case if it has been more active with an acceleration power of more than 10 to the 38 air power second with continuous over 10 to the 6, 10 to the 7 years the galactic center of atoms can explain most of the galactic cosmic rays about under TV to PVs which is good. Okay, what are the other possible ways to loop for these pavatrons? What are the multi-messenger signatures of these pavatrons? So as I said in the, quickly in the introductions we have some secondary electrons from pion decays which produce poms and crotons. Given the high-mine energy fields the x-rays are produced continuously to the gamma rays and this is what, given what we measure with S, this is the prediction of the flux in the TV range for instance and you can see this is on the top figure and you can see the measure flux by XMM. So the predicted flux from this pavatron in the TV is too faint compared to the diffuse thermal emissions. This is a black point on the figures seen by XMM. Another important channel for the signature of pavatrons is the neutrinos that are produced via pion decays and this is a prediction for various cut-off for instance in the protein spectrum and you see that the signal, the predicted signal is close to the detection sensitivity of kilomotor cube scale detectors. Okay, so I think I can, I come to my summary. So the search for pavatron and I hope I try to convince you it's very important to understand the origin of cosmic rays and especially the galactic cosmic rays. We have several candidate observed with S and the galactic center origin is one of the most important region and this is where we find the first or the most evidence of pavatrons. So given the risk data set, we saw a strong correlation between the gamma-ray luminosity and the molecular cloud distribution. The correlation is not linear and we have the first measurements of the radial cosmic ray density distribution in the 200 parts of the galactic center. The spectrum we measure in gamma-ray suggests that the black hole is likely the hydraulic cosmic ray accelerators which conduct the particles over more than at least a thousand years to peel the energies. And this is the first robust detection of the cosmic galactic pavatrons and the total energy powers is important about 10 to the 38 air cross seconds which is much more than the volumetric luminosity of the galactic center. So now the speculation is that if Sagittarius star has been more active in the past, it could explain at least most of the cosmic rays in the near regions between the Android TV or two TV's. So there are other candidate that may be possible, viable pavatrons and there are S analysis ongoing and this pavatron searches in the galactic center origin the Archi-Cyan project for the next ground-based gamma-ray observatory CTA. So with this region as is able to cover a vast number of cyan cases, we have a very rich data set accumulating over the last 10 years. Of course we have a detection of a pavatron, we have diffused emissions, large scales, a variety of sources emitting at the energy energies. There are possibly outflows in this region and maybe the base of Fermi bubbles and of course this region is also important for dark matter searches. So this is my last slide, I think I'm in time or almost and I leave you with my summary. Thank you. Thank you so much Emmanuel for the very interesting talk. I'm going to open the floor for questions. Please don't forget for the viewers to submit your questions through questions and answers in Google plus and also through Twitter via the hashtag love physics. So I'll take questions right now, there is a couple of questions already on the questions and answers but I'll go with the questions on the floor first. Anyone? Roberto we cannot hear you. You can hear me because I was mute. I like very much your talk Emmanuel, very nice. So I have a question regarding with dark matter. It's likely that the source, this pavatron is the Sagittarius A but is there a way to ensure that this for instance the Sagittarius A or for instance kind of exotic source like BEV dark matter decay that is quite lately I've been, it's very happy use for the explain this ice cube neutrinos at BEV or I don't know if it was. Yeah of course some pv decaying dark matter would produce some extended gamma ray emissions but here we have some from correlation of the signal with the target material. So in that sense I would say it is a conventional explanation of the diffuse emission we see in gamma rays I cannot exclude that there is some contribution of more exotic things such as decaying dark matter but yeah and also in case of decaying, yeah you need as you mentioned some very heavy dark matter which is possible of course but I don't know what to say. Yeah let's say we have some, yeah we try to argue that this is the most conventional explanation that produce most of the signal we detect in the gamma rays. So yeah this is what, of course we will have much more exposure in the next year with S and with the advent of CTA in that region and what we want at the end is to detect the cutoff in the diffuse emission and the study of for instance the cutoff in the energy cutoff in gamma rays, a detailed study of the energy cutoff in gamma rays with very good energy resolution may help you for instance to distinguish between some dark matter interpretation or more let's say yeah cutoff in the proton injection spectrum for instance. Also you can think of long term variability studies of the diffuse emission and if but quite long if there are some different activity of Sagittarius A star you may see some variability in the cutoff but yeah I would say that the one important thing is to detect the cutoff in the diffuse emissions and to measure very accurately the shape of the cutoff in the energy spectrum. That would be my yeah something important for the next years. I hope we answer at least partly to your question. Yeah yeah yeah now it's a little bit more I mean it's clear. Ok I have a question. Go ahead go ahead Herman. I have a question regarding well also the data because as far as I understand there is no H2 data in this analysis. Exactly yeah. Will it benefit in some point of H2 data incorporation here? Well what is important is of course the whole gamma spectrum from the low energy hand to the high energy hand so in that sense you may want to have S2 but what drive the results what happened in the highest energies of S2 with S2 you expect more flux sensitivity but given the very large photon statistics we accumulate with S1 it will take some time to even if we expect higher sensitivity with S2 it will take time to get the sensitivity we have with S1. There is a question from the questions and answers at Google plus. First he says from Marco Santander very nice talk can you explain what gas density measurements and radio profile models you use to derive to see our density? Yeah ok so the mass measurements in all the integration region is a crucial measurements and there are substantial uncertainties in this measurement. So and it is accounted in the error bars we see in the density distribution of cosmic rays that the mass measurements is at about a factor of two uncertainties. So to probe the density in this molecular clouds we use the CS line measurements with some transition. So this is based on the CS measurements and also we test we also compute the mass measurements using other tracers of the gas density such as CO or HCN and using this the mass measurements with other tracers still the one over here behavior is significantly preferred over the other dependency of the of the the radial profile. So yeah this is is it enough to answer or do you want more detail? Of course what it was kind of request to use different tracers for the mass estimate because they are biased in each of the tracers so they are not probing for instance the same density range for instance. So it was very important to use them and of course the density within the clouds is not homogeneous so but we don't know exactly how much the cloud are clamping for instance so it was crucial to confirm the robustness of the density measurements with other tracers but basically the mass measurements is within a factor of two uncertainties and is accounted in the error bars. So yeah he actually he got the answer and he thanks you for it. I think there is another question from here from Miguel Angel or not? Yes yes I actually have one. So very nice stuff Manuel. I actually have a question regarding the cutoff that you mentioned. I was wondering if there are any expectations from you know from models for the you know the central galactic source. What should we expect the cutoff if any? Are there any estimates about that? Are also observations compatible with what the people thought it would be? Can you comment on that? What we expect for instance in the cutoff of the proton spectrum this is what you mean or yes okay so of course we we we don't know at least we don't what if we we want we want power low acceleration to PV so to have some effective production. With efficient production of of proton activities PV energy we don't want cutoff in this region but formally of course there are there are some cutoff somewhere and we want to measure it but I'm not sure if like they are not strong there are no prediction basically because we see that there are PV so we need some some particular acceleration to be efficient up to this PV energies. We parametrize this in terms of a cutoff in the energies so meaning that we don't want a significant decrease or or loss in acceleration efficiency in the PV but we there is no prediction of this of this cutoff. Okay so what's the main limitation in your I mean when you make the measurement at the highest energies it's just a statistical limitation like your statistics you run out. Yeah basically we are in the statistically limited region so I guess with that we see CTA all that will be probably better. Yeah we will expect better much more statistic with CTA and and I think with S it will be difficult because now we are fighting with the systematics also in this in this region. Thematic of the of the background is is very yeah it's very difficult so this is now I would say that this is not only we could accumulate more statistics in the next few years with S but we would love to really understand much more in detail the the background systematics at NT these gamma ray energy for instance. Very very important and of course very difficult but crucial I would say. Thank you. There is a question from the questions and answers section is from Diego Alejandro Restrepo and he wants to know if you can explain how the center of the dark matter halo can be determined using this. The center of the dark matter halo. Okay so okay well so all the dynamics in this region is dominating so the gravitational potential in this region is dominated by the by the barionic matters. Okay so for instance the the the central the the central the position of the black hole is is located very precisely to coincide with the gravity center of the of the Milky Way. Given the for instance the star the star dynamics the very close by star dynamics and and we can given the the circle of the velocities of the stars we can as they are this is Keplerian motion which is measured and we can accurately measure the position of the of the of the black hole it is coincident with the gravity center for the dark matter halo if you assume sufficient relaxation time in this region between because dark matter and barions interact at some point so if the system is relaxed in principle there is no reason why the gravity center should not coincide. Of course if the system is not relaxed it might be the case so it means that the gravity center determined by the barions by the stars for instance can be different from the barocentral of the dark matter halo but given the the relaxation time at the galactic center it seems that it is relaxed so I would say that there is no reason why it should be displaced displaced or at least to my knowledge some yeah conventional explanation we have a relaxed system relaxed system so in principle the gravity center should coincide I hope it hope it it's answered partly to the question sorry thank you Manuel is there any questions from here because there is one more from the questions and answers from Diego Alejandro as well so that one unless yeah I have a very short question I mean about CTA if Manuel do you know more or less how many hours of observation require CTA to improve largely this observation by Hess or in the other way also how much time CTA will dedicate to this kind of searches observation okay so so the galactic center region and the inner few degrees of the galactic center is a priority of the consortium observation program of CTA it is a key science project so and a significant amount of observation is is foreseen in that region we in the in the first years of operation of CTA we expect about 500 hours in the in the few degrees of the galactic center so it will be a huge exposure and so the exposure will be much more than the one of S in about the yeah in in a few years the yeah the exposure will be at least yeah twice of S and on the other hand sensitivity will be improved with CTA the flex sensitivity so so we expect I I don't want to give numbers here because yeah it deserves a more quantitative explanation yeah determination but I would say in a yeah in several years in a couple to five years we we we hope to to yeah to to to reveal the the cut off in the in the deepest emissions in my head but on the other end this region will be also very complex for for for CTA because CTA will we'll have to to control the systematics and we will have to control the systematics very precisely in this region of course given the energy threshold we expect much more emission and also maybe maybe other contribution to the diffuse emission so the future with CTA will be bright I would say but also it will be challenge challenging to and difficult to to extract information given the we will have much more sources shining with given the the CTA sensitivity and also we we will have to work quite a lot on the system to control the systematics yeah in this region so yeah okay I don't know this is probably the last question that I'm going to ask you this is from Diego Alejandro Restrepo and it's what what is the key parameter to explain the PEV acceleration of hydronic particles is it magnetic field even horizon black hole size etc okay so the the key to put the key parameter is that we want to have hydronic interaction of course so we can think of some leptonic models in the in the galactic center for instance but the magnetic field it's quite high so about 100 micro goes so in that case the energy losses for electrons are very are severe so in the sense that the electrons lose very efficiently their energy through synchrotron losses for instance and also it is very difficult given exactly this argument to accelerate electrons up to hundred TV for instance so this basic fact I would say the challenge quite a lot the some leptonic interpretation of the of the gamma ray emission in the galactic center so this is yeah for the hydraulic emission this is what what would be the arguments on the measurements is that the there is a striking correlation with the with the the map the the the cloud distribution so if you want the electrons could not propagate let's say under TV electron could not propagate over 200% this is not possible in the galactic center environment so you will need many many leptonic source leptonic sources I would say so and this will require fine-tuning in the distribution of these sources for instance so this is that will be my my answer to so the real thing is that the measurements of the the Cosmic Ray densities which and the gamma ray measurements correlated with the the gas density distribution the location within the 10 porsec tells you that you don't have many astrophysical counterparts in that regions and yeah in the 10 porsec region to produce this energies over thousand years only the proton accelerated in the vicinity of the black hole are viable possibility I would say I hope this this help yes thank you man I think unless there is any more questions here I think I have one really really really quick question because I haven't been able to ask one regarding ice cube so ice cube is able to also have a sensitivity to this high energy cosmic rays right through production of pions in the atmosphere or did I get that wrong and how how complimentary is there the results against the results seen by by has well of course since it is pion interactions it is very difficult it is very easy to predict the the neutrino flux from the the GCP veterans and so far ice cube did not see any let's say extended emissions but who knows what we say is that it is within the reach of ice cube given the flux we predict but yeah it's difficult for me to say more about about the sensitivity of ice you it is within the reach of but this this neutrinos will be much lower in energy as detected by ice cube right much lower in energy than the gamma ray seen by yes principle there is no reason for that because if you for instance see one of the my first introduction for instance let me just slide number 11 in principle the number of neutrinos is very is is about the same of the gamma rays because the proton protons produce pi plus pi minus and pi zeros so yeah so in principle the numbers of neutrinos this they reached the same energies and they follow closely at least the indexes the index of the neutrino signal follows closely the the proton spectrum thinking thinking like a model builder because a lot of models that have been proposed to explain this pvx is that ice cube is a models of leptoquarks very high energy neutrinos produce a leptoquark in the ice and then this one the case so I was just wondering if if you or anyone that you've talked to have thought of any beyond the standard model scenarios where this pv protons can come from but no that would be I myself I do not think a lot about this but that that would be very interesting I think okay well I think I think there's no more questions and I want to really thank you for your time and for all the answers you've given us so really it was really interesting talk and I hope everyone that I watched the seminar the webinar enjoyed it I actually did a lot please don't forget to subscribe to the to the YouTube channel you can see this talk all over again it's going to be there forever as long as the internet exists and if you didn't have time to finish the talk obviously you can finish it later too so I really hope to see you for our 25th webinar and thank you all for for coming and I'm going to leave you really quickly with not the end is not here but well I'm just going to leave you but thank you very much and you guys everyone has a have a nice day thank you