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The ( [MATH] [MATH] ) evolution of the cloudy sequence is shown in Fig. where the cloudless cooling tracks are also shown for comparison. The effects of clouds on the surface boundary condition (Fig. ) essentially vanish at high and low |
[MATH] , and consequently, the cooling tracks of the cloudy models overlap the cloudless tracks in both limits. At intermediate [MATH] , where the cloud effects are maximal, the gravity of an object of a given mass is up to 0.08 dex lower in the cloudy models than for the cloudless case. For given values of ( [MATH] [M... |
can range for 0 to 0.1 dex, from 0 to 6% in radius, and 0 to 60% in age. These differences are modest but will become significant as brown dwarf studies become increasingly detailed and precise. |
3.2 Comparison with other calculations We validate our calculation by comparing with published results that are widely cited in the brown dwarf literature. This also offers a measure of the relative uncertainties that remain in modeling the evolution of brown dwarfs and, to some extent, to identify the model assumption... |
Baraffe et al. ( 2003 and our cloudy [MATH] sequence with the DUSTY00 models of Chabrier et al. ( 2000a and Baraffe et al. ( 2002 , respectively. We note that the COND03 and DUSTY00 models and ours use the same H/He EOS, the same interior composition and that there is no significant difference in our respective nuclear... |
Generally, the COND03 and DUSTY00 luminosities at a given age are slightly higher than ours. In both cases, however, the agreement is excellent for all masses at all ages above a few Myr, with differences below 0.05 dex for the cloudless case and below 0.09 dex (and usually much less) for the cloudy sequence. At young ... |
A comparison of our cloudless models with the evolution sequence of Burrows et al. ( 1997 (hereafter, B97) is shown in Fig. The agreement is not as good as we found with the COND03 models (Fig. ). One of the reasons is that the B97 models use a rather low value for the helium abundance of [MATH] , while the present mod... |
(Lodders, 2003 . To better compare with B97, we have computed a short sequence of models with [MATH] . This systematically shifts the luminosity curves downward and reduces the differences but not enough to reach the level of agreement seen in Fig. The B97 models also use the same EOS and nuclear reaction rates as in o... |
(Saumon et al., 1996 Atmosphere models of brown dwarfs have become increasingly more realistic over the past decade. Particularly significant changes in cloudless models since the work of Marley et al. ( 1996 |
are 1) the recognition of the role of the K I and Na I resonance doublets at optical wavelengths (Burrows et al., 2000 , 2) improved H CIA opacity (Borysow et al., 2001 ; Borysow, 2002 , 3) a new line list for TiO (Allard et al., 2000 ; Freedman et al., 2008 4) improved modeling of the condensation chemistry (Lodders, ... |
and NH (Freedman et al., 2008 . While the evolution is not sensitive to the details of the atmospheric opacity, the global opacity of the atmosphere largely accounts for the differences between the various evolution calculations for brown dwarfs. The above factors and cloud formation as well, all play a significant rol... |
show that the luminosity increases with the Rosseland mean atmospheric opacity as [MATH] , a relation confirmed by our non-solar cloudless evolution sequences. This, along with the choice of [MATH] |
explains most of the differences between our calculation and that of B97. Synthetic color-magnitude diagrams The availability of parallaxes for brown dwarfs (Dahn et al., 2002 ; Tinney et al., 2003 ; Vrba et al., 2004 provides absolute magnitudes and spectral fluxes that can be compared with a combination of evolution ... |
Tsuji & Nakajima ( 2003 Knapp et al. ( 2004 and Burrows et al. ( 2006 have suggested that variations in gravity (i.e. a spread in mass and age) account for the broadening. Other factors such as metallicity, unresolved binaries, and a range of cloud properties may also contribute to the scatter. Between the latest L dwa... |
(Dahn et al., 2002 ; Tinney et al., 2003 ; Vrba et al., 2004 , even though the bolometric luminosity decreases steadily with later spectral types (Golimowski et al., 2004 This was confirmed by the discovery of binary brown dwarfs with (coeval) components spanning the L/T transition and showing the |
[MATH] band flux reversal (Burgasser et al., 2006 ; Liu et al., 2006 . Even more intriguing, the binary fraction of early T dwarfs is twice as large as for other dwarfs and their spectra and colors are largely the result of the combined light of components of earlier and later spectral types (Burgasser et al., 2006 ; L... |
Detailed comparisons of our self-consistent evolution and spectra with spectroscopic data of a few late T dwarfs have been rather successful (Saumon et al., 2006 2007 , demonstrating that at least for the coolest brown dwarfs known the models, while admittedly imperfect, are fairly realistic. Fits of the entire spectra... |
In models with decreasing cloud thickness (increasing [MATH] ), the [MATH] color is the same as for [MATH] at the high- [MATH] end where the cloud opacity is always modest but shows a turnover to the blue that occurs at gradually higher [MATH] as the thinner cloud deck sinks below the average photosphere. At low [MATH]... |
In a very qualitative sense, the cloudy models show the turnover in [MATH] seen in the L/T transition objects but the turnover is much too gradual. Furthermore, the cloudy models do not show the brightening in the [MATH] band. A comparison with Fig. |
indicates that within the framework of the Ackerman & Marley ( 2001 cloud model , the L to T transition can be modeled by increasing [MATH] during the cooling of a brown dwarf. This idea is supported by the detailed analysis of the spectral energy distribution of several brown dwarfs (Cushing et al., 2008 While it is p... |
[MATH] at the transition, the Ackerman & Marley ( 2001 model does not provide a physical justification for this process. The transition could be the consequence of other cloud processes that are not captured in the Ackerman & Marley model. The rather simplistic cloud models developed so far are not adequate to understa... |
Color-magnitude diagrams have historically been one of the most powerful tools to understand stellar evolution. The difficulty in discovering and observing the intrinsically faint brown dwarfs has limited the the application CMDs in this brand of stellar astrophysics. Yet, a comparison of modeled magnitudes and colors ... |
4.1 Disk brown dwarfs We simulate a volume-limited population of field brown dwarfs by generating a random set of points in the mass-age parameter space with the mass chosen between 0.006 and 0.1 [MATH] , assuming a power law initial mass function (IMF) |
[EQUATION] where [MATH] is the space density of brown dwarfs in mass interval [MATH] . We choose [MATH] which is representative of the mass function of field brown dwarfs and consistent with the determination of Allen et al. ( 2005 We adopt a constant star formation rate (SFR) over the age of the Milky Way (0 – 10 Gyr)... |
We convert our sample of ( [MATH] , age) points to ( [MATH] ) values with our evolution sequences. This is shown in Fig. where we have used the cloudy evolution sequence with [MATH] . Objects with [MATH] above the upper limit of our surface boundary condition (2400 K) have been culled from the sample. The distribution ... |
[MATH] K. Figure illustrates that warm, low gravity brown dwarfs would be quite rare in the field under the assumption of a constant SFR rate over the age of the Galaxy. In contrast, the kinematics of L and T dwarfs indicates that the population may be as young as 0.5–4 Gyr (Zapatero Osorio et al., 2007 , a possibility... |
The pioneering work of Chabrier ( 2002 and the extensive studies of Burgasser ( 2004 Allen et al. ( 2003 and Allen et al. ( 2005 show how variations in the IMF and SFR affect one-dimensional distribution functions (such as the luminosity function) of field brown dwarfs. They offer a clear and detailed discussion of the... |
or on the luminosity function which collapses all objects from a two-dimensional distribution – for example, age and mass – into a one-dimensional distribution, binned in terms of [MATH] [MATH] , or spectral type. Our primary concern is to explore the two-dimensional distribution and its potential to reveal additional ... |
The most striking feature in these diagrams is that the color-magnitude distribution of the sample is rather different from that of the simulation, the former being more or less evenly weighted between L and T dwarfs while the simulation predicts that T dwarfs should be dominant if the IMF keeps rising towards low mass... |
At the upper limit of our calculation ( [MATH] K), the synthetic sequence joins the late M sequence nicely. The cloudless and cloudy sequences meet at [MATH] K as clouds play a minimal role at higher [MATH] (Fig. ). In the synthetic population, the [MATH] color of the objects with [MATH] |
becomes too blue by [MATH] , a problem that has plagued low temperature atmosphere models for several years. We find that the effect is less pronounced in [MATH] , where the difference is [MATH] More extensive calculations of the TiO and H O line lists, while substantially improving the agreement with observed spectra ... |
[MATH] (Chabrier & Baraffe, 2000 , but there is growing evidence that models of late L dwarfs are systematically underluminous for a given mass and age, as revealed by the first few dynamical mass measurements below the stellar mass limit (Ireland et al., 2008 ; Dupuy et al., 2008 . For late T dwarfs, absolute model fl... |
Small scale features in the synthetic CMDs are caused by the few cloudy atmosphere models that have converged to a poor solution, such as can be seen in Fig. they have no physical significance. By construction, these CMDs fold in a distribution of gravities and [MATH] based on reasonable assumptions that can be compare... |
On the other hand, the widening of the observed distribution in [MATH] of the mid to late L dwarfs cannot be explained solely by the range of gravity of the simulated population and appears to require variations in cloud properties. A combination of [MATH] and 2 populations appears sufficient to reproduce the observed ... |
(Burgasser et al., 2008 ; Cushing et al., 2008 ; Stephens et al., 2008 with the redder dwarfs having lower values of [MATH] Variations in metallicity increasingly affect the [MATH] color of late L dwarfs and could also contribute to the widening of the observed L sequence (Fig. 11 ), but probably not as much as variati... |
Our simulations indicate that a third parameter, related to cloud opacity, is also necessary to model the distribution of the mid-L to mid-T dwarfs colors. The transition from L to T spectral types is thought to require a rapid change in the cloud properties over a small range of [MATH] . The most important free parame... |
[MATH] , the gravity and the metallicity. Within this model, the transition from cloudy L dwarfs to the clear atmospheres of late T dwarfs can only be modeled by varying [MATH] . We find that the late L dwarf sequence requires [MATH] to 2, and that the transition dwarfs with [MATH] are fairly well matched with [MATH] c... |
(and perhaps gravity) could potentially match the CMD of L and T dwarfs. Admittedly, a color-magnitude diagram that involves only two band passes is a rather limited tool to study the transition. Detailed fits of the entire spectral energy distributions of [MATH] |
L1 to T6 dwarfs with these models fully support the present hypothesis as a trend of increasing [MATH] for T0 and later spectral types is found (Cushing et al., 2008 ; Stephens et al., 2008 |
Finally, the [MATH] colors of late T dwarfs are best reproduced by our [MATH] model as our cloudless models are somewhat too blue. Adding a thin cloud layer makes the models slightly redder and brings them in better agreement with the data. Late T dwarfs are expected to be cloudless however, as is indicated by detailed... |
[MATH] range have [MATH] , with a distribution that peaks sharply at [MATH] . Objects with [MATH] nearly all have cooled well below the [MATH] of any object detected so far. Unless the sample of BDs with parallaxes contains a large fraction of objects that are much younger than 5 Gyr (the average age in this simulation... |
[MATH] range to account for the observed spread of the sequence, even when considering the different [MATH] colors of the cloudless sequence of Burrows et al. ( 2006 It is conceivable that some late T dwarfs may not have completely cloudless atmospheres, which would increase the variation in near-infrared colors of lat... |
(Stephens et al., 2008 The dispersion caused by metallicity variations is discussed in §4.2.1. 4.2 A hybrid sequence of models To further illustrate the potential of population synthesis for the study of brown dwarfs, we have developed a simple model of the L/T transition. Based on the above discussion of the near-infr... |
atmosphere models for [MATH] K and of [MATH] models above 1400 K. The slight inconsistencies between the [MATH] values used in the evolution sequences and for computing the magnitudes are modest and can be ignored here (see §2.5). The colors are linearly interpolated in [MATH] at constant gravity between those two regi... |
across the L/T transition. This approach to modeling the L/T transition is similar to that of Chabrier ( 2002 who interpolated magnitudes in [MATH] between the DUSTY00 (Chabrier et al., 2000a |
and the COND (Chabrier & Baraffe, 2000 evolution sequences and to Burgasser et al. ( 2002 who used a slightly more elaborate interpolation between cloudy and cloudless magnitudes to approximate the effect of cloud clearing at constant [MATH] . Here we have recomputed the cooling with the hybrid boundary condition which... |
The ( [MATH] ) distribution for this hybrid evolution sequence, under the same IMF and SFR assumptions as in Fig. is shown in Fig. 12 Two new features are apparent. The most apparent is a bump in the upper envelope of the distribution, where the maximum gravity rises at the transition from the lower value of cloudy mod... |
[MATH] range of the transition. The effect can be clearly seen in the [MATH] distribution of the hybrid disk sequence where an excess of brown dwarfs of a factor of 2.1 occurs in the transition region compared to either the cloudy or the cloudless evolution sequences (Fig. 13 ). For the same reason, an excess also occu... |
[MATH] K as the cloud sinks in the atmosphere to levels where it no longer affects the surface boundary condition (Fig. ). This is a more gradual effect than our modeled L/T transition and the excess brown dwarf density is spread over a wider range of temperatures. Qualitatively, this effect is an inevitable consequenc... |
This excess of brown dwarfs in the transition is in apparent contradiction with Burgasser ( 2007 who found a minimum in the space density of transition dwarfs as a function of spectral type. There are two reasons for this. Our simulation of cloudy and cloudless evolution indicates a monotonous increase in the [MATH] di... |
Also shown on Fig. 16 are [MATH] determinations for various field and ultracool dwarfs in binaries. Given the small number of constrained objects and the current lack of detections at very low [MATH] , the agreement between the modeled and observed populations is reasonable. As spectral fitting becomes more precise, pa... |
The corresponding CMD is shown in Fig. 14 . The general agreement with the data is quite good as we have chosen the parameters of the hybrid model sequence for that purpose. Figure 14 is to be compared to Fig. 10 a for [MATH] and Fig. 10 d for [MATH] K. The region of interest is the transition region where the syntheti... |
4.2.1 Synthetic CMD with different assumptions In this section, we consider different assumptions for our population synthesis with the hybrid evolution sequence to estimate the importance of variations in the SFR, the IMF, and the role of unresolved binaries. These experiments are summarized in Fig. 15 where our fiduc... |
The importance of binaries in brown dwarf population synthesis has been pointed out by Chabrier ( 2002 and Burgasser ( 2007 Substellar objects have been the target of several high resolution imaging surveys aimed at establishing the statistics and properties of binary brown dwarfs. While the number of resolved systems ... |
(Burgasser, 2007 The mass ratio [MATH] distribution strongly favors equal mass binaries and can be approximated by [MATH] Burgasser ( 2007 and references therein). For the purpose of illustrating the role of binaries in the synthetic CMD we take a fraction |
[MATH] of the simulated single star population and assign each of them a companion of the same age and with a mass drawn from the above mass ratio distribution. The magnitudes of the components are combined to get the magnitudes of the (assumed) unresolved binary. The result is shown in Fig. 15 e, where unresolved bina... |
Finally, we consider the effects of variations in metallicity on the CMD. The large grids of cloudy atmosphere models with non-solar metallicity required for such a calculation are not yet available. We can presently explore the effect of metallicity on cloudless atmosphere models with [M/H]=-0.3, 0 and +0.3. These are... |
4.3 Color-Magnitude diagrams for clusters Brown dwarfs in galactic clusters offer the advantages of a uniform population with a known distance, metallicity and a very narrow age distribution compared to field objects. On the other hand, brown dwarfs in clusters are typically much more distant than typical field brown d... |
[MATH] end points of the modeled L/T transition are also apparent. All five synthetic clusters are shown in the [MATH] vs [MATH] CMD (Fig. 17 ), where objects with [MATH] K have been removed as they fall outside of our surface boundary condition in a regime where extrapolation is unreliable. This figure is to be compar... |
The most unusual (and to our knowledge, not previously predicted) feature of the cluster CMD is a backtracking loop along each isochrone except the oldest (500 Myr). It is not plotted on the youngest sequence (10 Myr) because it occurs at [MATH] K, above the limit of our evolution tracks. This feature arises because at... |
[MATH] to 100 Myr. This feature is also visible as a bump in the cluster LF, as seen in the simulations of Allen et al. ( 2003 4.3.1 Pleiades |
We compare our simple model of the L/T transition with the results of deep brown dwarf surveys in the Pleiades cluster. The relevant parameters of the cluster are its distance ( [MATH] pc, Percival et al. ( 2005 ), age ( [MATH] Myr, Martín et al. ( 1998 ), metallicity ([Fe/H] [MATH] Boesgaard & Friel ( 1990 ), and exti... |
(Moraux et al., 2003 ; Bihain et al., 2006 We generate a synthetic brown dwarf population with our hybrid evolution sequence ([M/H] [MATH] ), with [MATH] and stellar ages uniformly distributed between 105 and 115 Myr. The synthetic cluster sequence is compared with the data of Bihain et al. ( 2006 and Casewell et al. (... |
19 , respectively, where we assume that [MATH] and [MATH] pc. The Casewell et al. ( 2007 survey goes [MATH] magnitude fainter and shows a tighter L dwarf sequence. Both figures show that the modeled L dwarf sequence is too blue by [MATH] magnitude, too faint by [MATH] magnitude, or a combination of both effects. The |
Casewell et al. ( 2007 data (Fig. 19 ) goes deep enough to reveal two objects that appear to be early T dwarfs in L/T transition for the cluster, but they are a good magnitude fainter than the modeled population. Given that this hybrid evolution/color model agrees fairly well with the local field population of brown dw... |
The part of the modeled sequence that corresponds to the M and L spectral types ( [MATH] ) is [MATH] magnitude too blue in [MATH] . A younger age for the sequence would improve the agreement but a cluster age of [MATH] Myr is required to make it overlap the data – an implausible explanation. Figure 20 shows that this d... |
In the field, this feature is not discernible because all the primordial deuterium has been consumed in all but the very lowest mass objects for ages above 1 Gyr (Figs. and ). |
Figure 20 combines both the field and Pleiades data as well as the corresponding modeled sequences. The Pleiades M and L sequence objects are brighter than the those in the field due do their larger radii at a much younger age. Above the transition, the modeled sequences are both systematically too blue (or too faint, ... |
Conclusions Our calculation of the evolution of very low mass stars, brown dwarfs and planetary mass objects produces models that are quantitatively in very good agreement with published calculations. A detailed comparison shows some systematic differences that can be attributed to conductive energy transport, differen... |
We have developed a simple model for the cooling and color evolution of brown dwarfs across the L/T transition. This hybrid model predicts an excess of brown dwarfs in the [MATH] range of the transition by about a factor of 2 compared to purely cloudy or cloudless evolution. We have applied this hybrid evolution model,... |
We find that for our fiducial assumptions (power law IMF with [MATH] , constant SFR over the past 10 Gyr, single brown dwarfs only and [M/H]=0), the hybrid sequence reproduces the overall sequence from late M through late T dwarfs rather well, but not the dispersion along the sequence. Based on the near-infrared CMDs, ... |
[MATH] K in field brown dwarfs, in agreement with previous estimates. While a transition over such a narrow range of [MATH] appears to be “fast” considering the rather dramatic change in [MATH] colors across the transition, these values of [MATH] |
correspond to ages of 2 and 4 Gyr for a 0.06 [MATH] brown dwarf. The duration of the transition decreases rapidly with mass however, lasting only 0.15 Gyr for a 0.03 [MATH] |
brown dwarf. Better agreement can be obtained from late M to late L spectral types if the population is younger, such as with a constant SFR that started only 5 Gyr ago, by including binaries, or assuming that there is a wider range of cloud properties for later L spectral types. For a fixed metallicity, all simulation... |
color of the sequence turns over, corresponding to [MATH] . This feature is not visible in the data, however, most likely because it is blurred by variations in metallicity within the sample. We are not able to include metallicity variations in simulations of cloudy brown dwarfs, except in a very approximate way (Fig. ... |
The hybrid model fares somewhat worse when compared to the much younger brown dwarf population of the Pleiades. If the two faintest Pleiads reported are indeed T dwarf members of the cluster, then they provide strong evidence that the L/T transition occurs at lower [MATH] in lower gravity objects (i.e. younger or less ... |
At this time, the modest size of the sample of L and T dwarfs with known parallax and the lingering problems in modeling the atmospheres of cloudless and cloudy brown dwarfs restrict how much we can learn from the study of CMDs. Model limitations will eventually be overcome as new moelcular line lists are being develop... |
We acknowledge support from NASA grants NAG 2-6007 and NAG 5-8919 (M. S. M.). Support for this work, part of the Spitzer Space Telescope Theoretical Research Program, was provided by NASA. We thank A. J. Burgasser for thoughtful comments on the manuscript and J. R. Stauffer for useful discussions. |
Appendix A Typographical errors in Saumon, Chabrier & Van Horn (1995) Typographical errors have been found in the expressions for the thermodynamics of hydrogen and helium mixtures given in Saumon, Chabrier & Van Horn (1995, hereafter SCVH). The correct expressions are: |
[EQUATION] [EQUATION] [EQUATION] where the equation numbers are those of SCVH. The last correction affects the calculation of the contribution of the electrons to the ideal entropy of mixing. In practice, this matters only when the gas is nearly fully ionized, where the ideal entropy of mixing [MATH] (Eq. 53) is only a... |
# Source: arxiv 0808.2641 # Title: Fitting the Gamma-Ray Spectrum from Dark Matter with DMFIT: GLAST and the Galactic Center Region # Sections: all # Downloaded: 2026-03-02T07:58:15.018838+00:00 |
Fitting the Gamma-Ray Spectrum from Dark Matter with DMFIT: GLAST and the Galactic Center Region Abstract We study the potential of GLAST to unveil particle dark matter properties with gamma-ray observations of the Galactic center region. We present full GLAST simulations including all gamma-ray sources known to date i... |
Introduction The Gamma-ray Large Area Space Telescope (GLAST) was successfully launched on June 11, 2008. The main instrument onboard GLAST, the Large Area Telescope (LAT) represents an improvement by more than one order of magnitude over the sensitivity of its predecessor EGRET |
in the energy range from 20 MeV to 10 GeV, and extends the high energy coverage to about 300 GeV. These features make the LAT a tremendous tool for the indirect search for particle dark matter |
, expected in the best motivated particle models to be a weakly interacting massive particle (WIMP) with a mass in the 10-1000 GeV range |
. WIMPs occasionally pair-annihilate in dark matter halos, producing, as a result, Standard Model particles. Prompt production as well as decays, hadronization and radiative processes associated to the annihilation products give rise to stable species including gamma rays, in an energy range extending up to the WIMP ma... |
The signal from dark matter annihilation is proportional to the product of the particle pair-annihilation rate and to the particle number density squared along the line of sight. The latter quantity provides a guideline as to which regions of the gamma-ray sky are the most promising for the detection of a signal from d... |
, targets include the center of our own Galaxy, satellite galaxies of the Milky Way, nearby massive galaxies and clusters, as well as diffuse emission from the entire Galactic halo and the summed signal from unresolved sources at all redshifts in the extra-galactic diffuse gamma-ray flux. Numerous studies have addresse... |
). With the dawn of the GLAST era, theoretical speculations on indirect WIMP detection with gamma rays will soon face high-quality data and the challenge of the corresponding analysis. The main purpose of the present study is to introduce DMFIT, a numerical package that, interfaced with any spectral fitting routine, al... |
. We show fits to gamma-ray spectra simulated using the experimental response function of the LAT and the software analysis tools that will be used for the actual GLAST data analysis. We apply DMFIT to the case of an “isolated” gamma-ray source, such as might be associated to dark matter annihilation in Galactic dark m... |
The Galactic center region has long been considered a promising target to look for a signature from particle dark matter annihilation in gamma rays. First estimates of the detectability of a dark matter pair-annihilation signal from the center of the Galaxy date back 30 years |
. An incomplete list of recent references that discussed the detection of dark matter pair-annihilation in the Galactic center with gamma-ray observations includes |
. In particular, ref. discussed the dark matter interpretation of the gamma-ray excess reported by EGRET from the Galactic center |
; ref. and discussed a similar possibility for the high energy gamma-ray flux detected by HESS ; ref. presented studies where both the EGRET and the HESS data were simultaneously taken into account as a background to dark matter searches. In addition, recently, the GLAST collaboration gave in ref. |
a comprehensive and updated overview of the GLAST sensitivity to dark matter annihilation signals for several possible sources inside and outside the Galaxy, using the Collaboration’s current state of the art Monte Carlo and event reconstruction software. |
As far as the Galactic center region is concerned, in the present study we include all gamma-ray sources known to-date within an angle of 4 degrees from the Galactic center, in addition to the diffuse Galactic gamma-ray emission. Of special importance is the question of how to properly model the innermost sources, asso... |
The main scopes of the present study are to: 1. present the DMFIT tool, and show examples of its application; 2. provide an updated template for the gamma-ray sources potentially relevant to dark matter searches in the Galactic center region; |
3. assess the capabilities of GLAST to provide information on particle dark matter properties such as the mass and the dominant annihilation mode, both in virtually “background-free” setups and in the complex gamma-ray environment of the Galactic center; |
4. study the theoretical bias that background modeling and theoretical priors (such as the dominant annihilation mode) produce in the estimation of the fundamental particle properties of dark matter from gamma-ray data. |
The paper is organized as follows: sec. 2.1 introduces the DMFIT tool and 2.2 provides details on the GLAST simulations; sec. 3.1 discusses the gamma-ray sources included in the simulations, and 3.2 describes the particle dark matter models; sec. shows examples of applications of DMFIT to gamma-ray spectra produced by ... |
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