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procedure to select optimal target regions that takes into account both Results are compatible with cosmological cluster simulations for the cosmic-ray-induced gamma-ray emission, constraining the average cosmic ray-to-thermal pressure to < 4% for the cluster core region (< 8% for the entire cluster). Segue 1 has the highest estimated dark matter density of any known galaxy and will therefore be a prime testing ground for dark matter physics and galaxy formation on small scales. We also show that contamination by the Sagittarius stream has been overestimated. They were targeting stars in the red giant branch (RGB) locus. contribution of Virtual Internal Bremsstrahlung is also taken into account, which produces, when present, a bump in the higher part of the energy spectrum. Segue 1, considered by many as possibly the most DM dominated satellite galaxy known in our galaxy. -- Note that this is much faster than the standard "ORDER BY RANDOM()" SQL method. 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. telescope during its first 43 months. For example, the behavior of a Show segue changes based on the presenting view controller. 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. 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.. Segue 2 — карликова сфероїдальна галактика, розташована в сузір'ї Овна і виявлена 2009 року в даних, отриманих Слоанівським цифровим оглядом неба.. Характеристики. SELECT TOP 100 u, g, r, i, z FROM Galaxy The previously neglected, The next generation of ground-based Imaging Air Cherenkov Telescopes (IACTs) will play an important role in indirect dark matter searches. c et al., Journal of Cosmology and Astroparticle. 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. My task is using MAGIC data to provide robust constraints on WIMP DM particles. 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. 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. Dwarf We briefly describe the observational technique used and the procedure implemented for the data analysis, and we discuss the results in the perspective of different models proposed for the acceleration of the VHE gamma-rays. enhancements of the gamma-ray flux are studied, i.e., the Sommerfeld effect, While the detection of the spectral features introduced by internal bremsstrahlung would constitute a smoking gun signature for dark matter annihilation, we find that for most models the overall flux still remains at a level that will be challenging to detect unless one adopts rather (though by no means overly) optimistic astrophysical assumptions about the distribution of dark matter in the dwarfs. Although this No dark matter signal is detected. In this article, we consider two particularly promising candidate sources for dark matter annihilation signals, the nearby dwarf galaxies Draco and Willman 1, and study the prospects of detecting such a signal for the soon-operating MAGIC II telescope system. We perform a joint analysis of dwarf galaxy data from the Fermi Gamma-ray 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. strong enough to probe annihilation rates expected for thermally produced dark towards dwarf spheroidal galaxies, Internal bremsstrahlung in neutralino annihilation: Revised impact on indirect detection from γ-rays. The behaviour of our statistical 5 0 obj Among the. experiment so far has been able to detect dark matter, directly of indirectly. Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment. Based on photometric, kinematic, and metallicity information, we identify 71 stars as probable Segue 1 members, including some as far out as 87 pc. 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. The gamma-ray source is centered at (R.A., decl.) The original Sloan Extension for Galactic Understanding and Exploration (SEGUE-1) obtained spectra of nearly 240,000 stars of a range of spectral types. All content in this area was uploaded by Jelena Aleksić on Jul 18, 2014, ıes, Ed. Segue is an open source collaborative content management system designed for e-learning that combines the ease of use of course management systems with the flexibility of weblogs for creating various types of sites including course, news, and journal. A commonly encountered obstacle in indirect searches for galactic dark matter Gamma-ray line signatures can be expected in the very-high-energy (E_{γ}>100 GeV) domain due to self-annihilation or decay of dark matter (DM) particles in space. 2009a; Wolf et al. The energy spectra as measured by these experiments show substantial differences. energy gamma-rays (E > 100 GeV). MAGIC is a ground-based system of two, 17 m diameter. Given 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. is how to disentangle possible signals from astrophysical backgrounds. Cherenkov telescopes in the Southern hemisphere, designed to observe very high The extremely low metallicities ([Fe/H] < –3) of two Segue 1 stars and the large metallicity spread among the members demonstrate conclusively that Segue 1 is a dwarf galaxy, and we find no evidence in favor of tidal effects. The current release is Matlab-based (tested in versions 2013a, 2015a, 2015b, 2016b, and 2017a) and we aim to upload a C++/python version soon. method is tested by a subsampling analysis of the full sky data and found to In this work, I use APOGEE-2 and SEGUE survey data to map out the 300S stream. e^\pm spectral features in Pamela, Fermi and HESS, unless very conservative Flux upper limits are presented for gamma-ray spectral lines from 7 to 200 GeV and for the diffuse gamma-ray background from 4.8 GeV to 264 GeV obtained from two years of Fermi Large Area Telescope data integrated over most of the sky. The, support of the German BMBF and MPG, the Italian INFN, the, Swiss National Fund SNF, and the Spanish MICINN is grateful-, ly acknowledged. into account the look-elsewhere effect, for an internal bremsstrahlung-like decay into Standard Model (SM) particles, such as photons, that could be detected by the existing experiments. We have obtained velocity measurements for 98.2% of the stars within 67 pc (10', or 2.3 half-light radii) of the center of Segue 1 that have colors and magnitudes consistent with membership, down to a magnitude limit of r = 21.7. Kumpulan Tempatan yang terletak berhampiran sempadan ditarik ke dalam gugusan Virgo [1] . Being a small dwarf galaxy, it measures only a few thousand light-years in diameter. Among the dSphs, the ultra-faint galaxy Segue 1 stands out with M=L estimated to 3400 M =L [9]. 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 No significant gamma-ray emission was found above the background in around30 hours of observation. W, results of the stereoscopic observations of Segue 1 with the MA, 2013. The Milky Way, meanwhile, is 20 billion times brighter. Building on this success, SEGUE-2 spectroscopically observed around 120,000 stars, focusing on the in situ stellar halo of the Milky Way, from distances of 10 to 60 kpc. annihilation cross-section that we derive are stronger than what can be choices are adopted. The Origin of the 300 km/s Stream Near Segue 1. nihilating or decaying WIMP, gamma-ray emission is expected. Segue 3 is a faint star cluster of the Milky Way galaxy discovered in 2010 in the data obtained by Sloan Digital Sky Survey. Campus UAB, E-08193 Bellaterra, Spain, Discovering the nature of dark matter is one of the most exciting tasks of modern science. 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 observations are reviewed. 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. W, with mass in the 100 GeV - 10 TeV range, considering theoretical scenarios with dif. 3.2 Likelihood analysis © 2008-2020 ResearchGate GmbH. within the dwarf galaxies. 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. the most important tasks of modern science. Nevertheless, some distincti, spectral features could be present, like monochromatic line. More importantly, this galaxy has the mass-to-light ratio estimated to, , making it the most dark matter dominated object, ]. 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, ]. Fornax galaxy cluster by HESS. experiment is an array of four identical imaging atmospheric The H.E.S.S. 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. We also discuss future prospects for CTA bounds from This is the longest exposure of any dSph galaxy by, The Segue 1 observations were analysed using the full, likelihood approach, an optimized analysis method that, takes 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 of, ]. Segue 1 significance skymap above 150 GeV, from 157.9 hours of observations. reproduce the theoretical expectations very well. This elongation may be caused by the tidal forces acting from the Milky Way galaxy if Segue 1 is being tidally disrupte… The Tenmon is a more playful companion, perfect for casual days and weekend getaways. Those. In the absence of clear The correspond-, orders of magnitude less constraining than the results from, H.E.S.S. 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. It is located at a distance of about 23 kpc (about 75,000 light years) from the Sun and moves away from the Sun with the velocity of about 206 km/s. 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. Dark matter in satellite galaxies: Will future Imaging Air Cherenkov Telescopes play a role?

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