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strong enough to probe annihilation rates expected for thermally produced dark line searches in the central Galactic Halo [, one to two orders of magnitude weaker than the Fermi-LA, analyses. analysis and additional data will be necessary to rule out or confirm this © 2008-2020 ResearchGate GmbH. within the dwarf galaxies. The mass within the half-light radius is 5.8+8.2 – 3.1 × 105 M ☉. have been derived in different particle physics scenarios. It is located in the Pegasus constellation at the distance of about 17 kpc from the Sun and moves away from it with the velocity of 167.1 ± 1.5 km/s.. into account the look-elsewhere effect, for an internal bremsstrahlung-like errors reflect the systematic uncertainty in the distribution of dark matter ... of two Segue 1 stars and the large metallicity spread among the members demonstrate conclusively that Segue 1 is … Note that with a 1 km s −1 velocity dispersion, Segue 1 would have (M 1/2 /L 1/2) 150 within the half-light radius (if interpreted as a system in equilibrium) and therefore would still be among the most dark-matter-dominated satellites of the Milky Way (Walker et al. The Sagittarius Dwarf Spheroidal Galaxy (Sgr dSph), also known as the Sagittarius Dwarf Elliptical Galaxy (Sgr dE or Sag DEG), is an elliptical loop-shaped satellite galaxy of the Milky Way.It contains four globular clusters, with the brightest of them – NGC 6715 (M54) – being known well before the discovery of the galaxy itself in 1994. However, at least for the case of Willman 1 observed by CTA, boost factors may be below 10, even without considering the effect of substructures or the Sommerfeld enhancement. We present the results of the stereoscopic observations of Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. signals, constraints on the Dark Matter particle annihilation cross-section an interesting improvement and may become better than those from the current or observation campaigns on dwarf satellite galaxies of the Milky Way were After correcting for the influence of binary stars using repeated velocity measurements, we determine a velocity dispersion of 3.7+1.4 – 1.1 km s–1. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. Nonadaptive segues are provided for apps that must also run on iOS 7, which does not support adaptive segues. The kinematic signature of 300S was first discovered in spectroscopic studies of the Segue 1 dwarf galaxy as a separate stellar population moving at 300 km/s. Lastly, results are interpreted in the light of v. dark matter annihilation and decay scenarios. 5 0 obj The resulting, sample is to be used as a test area of the ever-e, The source chosen as the most suitable candidate is the, ultra-faint dSph galaxy Segue 1. Scientists have found the darkest known galaxy, a treasure trove of around 1,000 ancient, small and dim stars located just outside the Milky Way. WIMPs are expected to annihilate or. spectral information of individual photon events from a sample of seven dwarf Among the targets suitable for dark matter searches, dwarf spheroidal galaxies are considered to be excellent candidates and, among them, Segue 1 stands out with mass-to-light ratio estimated to be of the order of 1000. Investigate the non-thermal processes in the Universe leading to particle acceleration and gamma ray radiation. The, dark matter particle mass takes values from the 100 GeV -, Furthermore, no additional boosts to the signal, either from, presence of substructures or from quantum effects were, In particular, constraints are calculated for the follow-, its for leptonic channels are even more stringent than the, constraints from this work are at least an order of magni-, tude stronger than the previous most sensitive MA, ]. With a total luminosity less than that of a single bright red giant and a V-band mass-to-light ratio of 3400 M ☉/L ☉, Segue 1 is the darkest galaxy currently known. towards dwarf spheroidal galaxies, Internal bremsstrahlung in neutralino annihilation: Revised impact on indirect detection from γ-rays. With almost 160 hours of good quality data, this is the deepest observational campaign on any dwarf galaxy carried so far by any Imaging Air Cherenkov Telescope. Furthermore, we estimate the sensitivity of Cherenkov Telescopes for monochromatic line signals. Although this The gamma-ray source is centered at (R.A., decl.) Kumpulan Tempatan ialah sebuah kumpulan galaksi yang termasuk galaksi kita, Bima Sakti.Kumpulan ini terdiri daripada lebih 35 galaksi, dengan pusat graviti terletak di antara Bima Sakti dan Galaksi Andromeda.Galaksi Kumpulan Tempatan meliputi diameter 10 juta tahun cahaya (lihat 1 E+22 m untuk perbandingan jarak) dan mempunyai bentuk binari (dumbel). The preference, howe, given to the astrophysical sources of con, whose spectral distributions are nicely described, in majori-, analysis tools and methods of IACTs are adapted for such, signals, at the expense of sources whose emissions are pre-, dicted to contain some distinctive spectral features. would be a fascinating possibility, we caution that a much more dedicated telescope during its first 43 months. The notion of dark matter has been present for almost a, Observational evidence on all scales and cosmological, predictions indicate that dark matter represents almost 85%, of the matter content of our Universe, an almost 25% of its. We perform a Cn. Segue 1, considered by many as possibly the most DM dominated satellite galaxy known in our galaxy. option. Each survey has a number of different programs. ResearchGate has not been able to resolve any citations for this publication. Dwarf galaxy dynamics shows that they are Dark Matter-dominated environments. stringent constraints currently available, for a large range of DM masses and a W, with mass in the 100 GeV - 10 TeV range, considering theoretical scenarios with dif. of both instruments were replaced by the more advanced, DRS4-based configurations; by the end of 2012, among, other improvements, the camera of MAGIC-I w, to the exact replica of that of MAGIC-II [, performance of the system varied during the total period, of Segue 1 observations; therefore, data from each of the, different telescope states are analyzed separately, After the selection and data reduction procedures of, the MAGIC standard analysis chain, the total effecti, observation time amounted to 157.9 hours of good-quality, data. For monochromatic γ-ray line emission, flux limits of (2×10^{-7}-2×10^{-5}) m^{-2} s^{-1} sr^{-1} and (1×10^{-8}-2×10^{-6}) m^{-2} s^{-1} sr^{-1} are obtained for the central part of the Milky Way halo and extragalactic observations, respectively. In the absence of clear 241302 doi:10.1103/PhysRevLett.107.241302. Messier 54 (juga dikenali sebagai M54 atau NGC 6715 adalah kelompok globul dalam buruj Sagittarius.Ia telah ditemui oleh Charles Messier pada tahun 1778 dan kemudiannya dimasukkan dalam katalog objek seperti komet.M54 mudah dijumpai di langit, dekat dengan bintang ζ Sagittarii.Walau bagaimanapun, ia tidak dapat dileraikan menjadi bintang individu walaupun dengan teleskop amatur yang lebih besar. The original Sloan Extension for Galactic Understanding and Exploration (SEGUE-1) obtained spectra of nearly 240,000 stars of a range of spectral types. Koushiappas, Physical Re, D 86 (2012) 021302 doi:10.1103/PhysRevD.86.021302, T. Bringmann et al., Journal of Cosmology and Astroparticle, Physics 07 (2012) 054 doi:10.1088/1475-7516/2012/07/054. The stellar kinematics of Segue 1 require very high mass-to-light ratios unless the system is far from dynamical equilibrium, even if the period distribution of unresolved binary stars is skewed toward implausibly short periods. Using data collected with the H.E.S.S. SEGUE-2 checked object or a SEGUE-1/southern survey target BossTarget The boss_target1 field is a bit mask specifying which BOSS target categories the object was selected in. The obtained up-, acy of the considered model is more relevant, and limits, order of magnitude more constraining than the ones for the, case of less significant VIB contribution (, considered channels, estimated bounds are up to two - three, orders of magnitude stronger than for the annihilation into. limits are the strongest bounds, for the considered channels, from dSph observations by IACTs, and, for some models, and dark matter particle masses, even more constraining, The acquired results represent an improvement, with, respect to the previously most sensitive MA, searches, of an order of magnitude. Recently, the Galactic center has been reported to be a source of very high energy (VHE) gamma-rays by the CANGAROO, VERITAS, and HESS experiments. 2009a; Wolf et al. general speCifiCations: Dimensions: Measuring 2.1 x 2.6 x 4.3 inches Weight: 8.0 oz. As an example, we review the gamma-ray dark matter detection prospects from Draco dwarf spheroidal galaxy at the MAGIC stereoscopic system and the CTA project. experiment so far has been able to detect dark matter, directly of indirectly. No significant gamma-ray emission was found above the background in around30 hours of observation. Cn. Segue 2 has a luminosity just 900 times that of our sun, the researchers report. Figure 9-1 lists the adaptive segues and how they behave in your app. We derive new bounds on decaying Dark Matter from the gamma ray measurements Ƶ~2Bn�)��m��/��\��[��Ӭ�)3�d����Nf5�_M�1|�S0No�����0�j�� aѦ��{L��NYhl��/�eV�#���VX9��m�>�~����j�T��C��60_��ա��y MAGIC can hunt this signature in the night sky. We revise the impact of internal bremsstrahlung photons in the context of the constrained minimal supersymmetric standard model on gamma-ray dark matter annihilation searches. This is the largest survey ever ... 17 m diameter IACTs, located at the Observatory Roque de los Mucha- Halo Galaksi menjangkau luar tetapi terhad dalam saiz oleh orbit dua satelit Bima Sakti, Awan Magellan Besar dan Kecil di perigalaktikon pada ~180,000 tahun cahaya. enhancements of the gamma-ray flux are studied, i.e., the Sommerfeld effect, Annihilation, Observation of Gamma Rays from the Galactic Center with the MAGIC Telescope, Dark matter line search using a joint analysis of dwarf galaxies with The energy spectra as measured by these experiments show substantial differences. De-, as the squared ratio of the masses of the scalar and dark, VIB contribution is the most pronounced. MAGIC is a ground-based system of two, 17 m diameter, IACTs, located at the Roque de los Muchachos Observatory, a.s.l.). It was discovered by Beth Willman, Julianne J. Dalcanton, David Martinez-Delgado, and Andrew A. galaxies. Several Nominal positions of Segue 1 and η Leo are marked with the square and the star, respectively. from direct dark matter annihilation (decay) into photon(s), or pronounced peak towards the kinematic limit from emis-, sion of virtual internal bremsstrahlung (VIB) photons [, The IACTs are observatories that deal with great v, of scientific objectives. SEGUE-2 covers plate numbers 3000 to 3509; all spectra on these plates were measured with the SDSS-I/-II spectrograph. For an, Addressing the question about the importance of future Imaging Air Cherenkov Telescopes (IACTs) for indirect detection of Dark Matter (DM), I will review the results of a paper by Bringmann et al. 041301 doi:10.1103/PhysRevLett.110.041301. Segue 1 significance skymap above 150 GeV, from 157.9 hours of observations. stream Dark matter particle annihilation or decay can produce monochromatic gamma-ray lines and contribute to the diffuse gamma-ray background. Comment: 10 pages, 4 figures, minor changes, matches the published version (JCAP). decay into Standard Model (SM) particles, such as photons, that could be detected by the existing experiments. The Local Group is the galaxy group that includes the Milky Way.It has a total diameter of roughly 3 megaparsecs (9.8 Mly), and a total mass of the order of 2 × 10 12 solar masses (4.0 × 10 42 kg). We We give cross-section upper limits and decay lifetime lower limits for dark matter models that produce gamma-ray lines or contribute to the diffuse spectrum, including models proposed as explanations of the PAMELA and Fermi cosmic-ray data. It features a quartz movement housed in a stainless steel case and protected by a sapphire crystal. Dwarf galaxies show no evidence of a gamma-ray line between 10 GeV We present the results of a comprehensive Keck/DEIMOS spectroscopic survey of the ultra-faint Milky Way satellite galaxy Segue 1. SEGUE could be used for spatial phase unwrapping in other applications such as X-ray phase contrast imaging, synthetic aperture radar interferometry, and 3D shape measurement or profilometry. that such signals are most likely subdominant, the search for pronounced For a DM particle mass of 1 TeV, limits on the velocity-averaged DM annihilation cross section ⟨σv⟩_{χχ→γγ} reach ∼10^{-27} cm^{3} s^{-1}, based on the Einasto parametrization of the Galactic DM halo density profile. All content in this area was uploaded by Jelena Aleksić on Jul 18, 2014, ıes, Ed. γ-ray instrument, upper limits on linelike emission are obtained in the energy range between ∼500 GeV and ∼25 TeV for the central part of the Milky Way halo and for extragalactic observations, complementing recent limits obtained with the Fermi-LAT instrument at lower energies. We search for dark matter particles with mass in the 100 GeV -10 TeV range, considering theoretical scenarios with different final state Standard Model particles, annihilation with internal bremsstrahlung and monochromatic line signals. The Perseus galaxy cluster was observed by the MAGIC Cherenkov telescope for a total effective time of 24.4 hr during 2008 November and December. New interesting targets are recently found that are extremely dark matter dominated. To this end, we use a new adaptive All rights reserved. obtained from the observation of dwarf galaxies and, at least for the model employ a novel statistical method that takes into account the spatial and Segue 3 is a faint star cluster of the Milky Way galaxy discovered in 2010 in the data obtained by Sloan Digital Sky Survey. Given that no significant gamma-ray, signal was found, the limits are derived for annihilation and, decay rates assuming various dark matter models. There-, fore, in this work, an alternative analysis approach is used, nition of characteristic signatures dark matter interactions, mal advantage of the spectral information, and almost sole-, ly through the inclusion of the a priori knowledge on the, expected gamma-ray spectrum in the likelihood, it achieves, significantly better sensitivity than the method currently. Dark matter signals from Draco and Willman 1: prospects for MAGIC II and CTA, Dark Matter searches with H.E.S.S. A LEKSI C´1,M.DORO 2,S.LOMBARDI 3,D.NIETO 4 ON BEHALF OF THE MAGIC C OLLABORATION AND M. F ORNASA 5 1 Institut de F ´ sica d Altes Energ ´ es, Ed. Physics 06 (2011) 035 doi:10.1088/1475-7516/2011/06/035. For the first time in such a study, we fully take into account the effect of internal bremsstrahlung, which has recently been shown to considerably enhance, in some cases, the gamma-ray flux at the high energies where Atmospheric Cherenkov Telescopes operate, thus leading to significantly harder annihilation spectra than traditionally considered. Such a signal would be readily distinguishable from astrophysical γ-ray sources that in most cases produce continuous spectra that span over several orders of magnitude in energy. Regarding the decay into the final state channel-, s, the dark matter particle lifetime is found to be of order, er limits estimated from the Fornax galaxy observations, with H.E.S.S., but from one to two orders of magnitude less, constraining (depending on the channel) than the bounds, Search for monochromatic line is done assuming direct, annihilation into two photons, and one photon and, Although these processes are highly loop suppressed, poten-, tial detection of line-like feature would provide a firm proof, of the dark matter existence, and also reveal some infor-, mation regarding the nature of its particle. Plate numbers 3510 or larger are BOSS plates, taken with the new BOSS spectrograph. However we note that because the signal aperture is matched to the angular size of the MAGIC PSF, this truncation has a negligible impact on the sensitivity of the analysis. of (i) the isotropic residual (extragalactic) background by Fermi and (ii) the SDSS Legacy and SEGUE-1 cover plate numbers from 266 to 2974. -- Note that this is much faster than the standard "ORDER BY RANDOM()" SQL method. Segue 1 has a noticeably elongated (ratio of axes ~ 2:1) shape with the half-light radiusof about 30 pc. SEGUE-2. Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. Search for Photon-Linelike Signatures from Dark Matter Annihilations with H.E.S.S. The correspond-, orders of magnitude less constraining than the results from, H.E.S.S. It describes the shape of the expected, spectrum and gives the number of photons produced above, a given energy threshold for the dark matter scenario in, question. Here are presented the details on the latest dark matter, presented, together with the motivation behind the choice of, Segue 1 as a suitable dark matter target. experiment is an array of four identical imaging atmospheric West in 2005.. Properties. massive particles (WIMPs), that are of non-baryonic nature, produced thermally in the early Universe, and are stable on, cosmological scales. upper and lower, limits were calculated instead, for different models of dark, The considered scenarios include: annihilation and decay, into the final state SM particles, direct annihilation and, decay into photon(s) and 3-body annihilation with virtual, internal bremsstrahlung (VIB) contribution. Twenty paper disks (9 mm diameter) were immersed in the experimental solutions [0.1% CPC, 0.2% CPC, 2.5% NaOCl, 2.0% CHX (F.G.M., Joinville, SC, Brazil), and sterile distilled water] for 1 min and then 4 paper disks were placed over the BHIA surface in each agar plate. of high energy photons is enhanced by an order of magnitude in the stau coannihilation region, where the signal remains still at least three orders of magnitude below the sensitivity of the instruments. By using the full likelihood analysis, we take complete advantage of the distinct features expected in the gamma ray spectrum of Dark Matter origin, achieving better sensitivity with respect to the standard analysis chains. More importantly, this galaxy has the mass-to-light ratio estimated to, , making it the most dark matter dominated object, ]. Segue 1’s velocity dispersion by Geha et al. The observable flux in the MAGIC analysis of Segue 1 is therefore reduced by a factor of ˘1.6 with respect to the LAT analysis of the same target. The Origin of the 300 km/s Stream Near Segue 1. The behaviour of our statistical Segue 2 is a dwarf spheroidal galaxy situated in the constellation Aries and discovered in 2009 in the data obtained by Sloan Digital Sky Survey.The galaxy is located at the distance of about 35 kiloparsecs (35,000 parsecs; 110,000 light-years) from the Sun and moves towards the Sun at a speed of 40 km/s. Discovering the nature of dark matter is one of the most exciting tasks of modern science.

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