scholarly journals J-factor estimation of Draco, Sculptor, and Ursa Minor dwarf spheroidal galaxies with the member/foreground mixture model

2020 ◽  
Vol 499 (3) ◽  
pp. 3320-3337 ◽  
Author(s):  
Shun-ichi Horigome ◽  
Kohei Hayashi ◽  
Masahiro Ibe ◽  
Miho N Ishigaki ◽  
Shigeki Matsumoto ◽  
...  

ABSTRACT Dwarf spheroidal galaxies (dSphs) are promising targets of indirect detection experiments searching for dark matter (DM) at present Universe. Towards robust prediction for the amount of signal flux originating in DM annihilation inside dSphs, a precise determination of DM distributions as well as J-factors of the dSphs is particularly important. In this work, we estimate those of Draco, Sculptor, and Ursa Minor dSphs by an improved statistical method in which both foreground stars and dSph member stars are simultaneously taken into account. We define the likelihood function of the method as the so-called conditional one to remove sampling bias of observed stellar data. This improved method enables us to estimate DM distributions and J-factors of the dSphs directly from observed stellar data contaminated by foreground stars without imposing stringent membership criteria on the measured quantities.

2004 ◽  
Vol 220 ◽  
pp. 365-366
Author(s):  
J. R. Kuhn ◽  
D. Kocevski

A simple and natural explanation for the dynamics and morphology of the Local Group Dwarf Spheroidal galaxies, Draco (Dra) and Ursa Minor (UMi), is that they are weakly unbound stellar systems with no significant dark matter component. A gentle, but persistent, Milky Way (MW) tide has left them in their current kinematic and morphological state (the “parametric tidal excitation”). A new test of a dark matter dominated dS potential follows from a careful observation of the “clumpiness” of the dS stellar surface density.


2019 ◽  
Vol 490 (1) ◽  
pp. 231-242 ◽  
Author(s):  
Manoj Kaplinghat ◽  
Mauro Valli ◽  
Hai-Bo Yu

ABSTRACT We point out an anticorrelation between the central dark matter (DM) densities of the bright Milky Way dwarf spheroidal galaxies (dSphs) and their orbital pericenter distances inferred from Gaia data. The dSphs that have not come close to the Milky Way centre (like Fornax, Carina and Sextans) are less dense in DM than those that have come closer (like Draco and Ursa Minor). The same anticorrelation cannot be inferred for the ultrafaint dSphs due to large scatter, while a trend that dSphs with more extended stellar distributions tend to have lower DM densities emerges with ultrafaints. We discuss how these inferences constrain proposed solutions to the Milky Way’s too-big-to-fail problem and provide new clues to decipher the nature of DM.


2002 ◽  
Vol 124 (6) ◽  
pp. 3222-3240 ◽  
Author(s):  
M. Bellazzini ◽  
F. R. Ferraro ◽  
L. Origlia ◽  
E. Pancino ◽  
L. Monaco ◽  
...  

2004 ◽  
Vol 611 (1) ◽  
pp. L21-L24 ◽  
Author(s):  
Mark I. Wilkinson ◽  
Jan T. Kleyna ◽  
N. Wyn Evans ◽  
Gerard F. Gilmore ◽  
Michael J. Irwin ◽  
...  

2005 ◽  
Vol 130 (1) ◽  
pp. 95-115 ◽  
Author(s):  
Slawomir Piatek ◽  
Carlton Pryor ◽  
Paul Bristow ◽  
Edward W. Olszewski ◽  
Hugh C. Harris ◽  
...  

2003 ◽  
Vol 588 (1) ◽  
pp. 326-330 ◽  
Author(s):  
J. S. Gallagher ◽  
G. J. Madsen ◽  
R. J. Reynolds ◽  
E. K. Grebel ◽  
T. A. Smecker‐Hane

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