J/ApJ/821/54 XMM spectral analysis of Draco dSph (Sonbas+, 2016)
X-ray sources in the dwarf spheroidal galaxy Draco.
Sonbas E., Rangelov B., Kargaltsev O., Dhuga K.S., Hare J., Volkov I.
<Astrophys. J., 821, 54-54 (2016)>
=2016ApJ...821...54S 2016ApJ...821...54S (SIMBAD/NED BibCode)
ADC_Keywords: X-ray sources ; Active gal. nuclei ; Photometry, SDSS ;
Photometry, infrared
Keywords: dark matter; galaxies: dwarf; galaxies: individual: Draco dwarf;
novae, cataclysmic variables; stars: carbon; X-rays: binaries
Abstract:
We present the spectral analysis of an 87ks XMM-Newton observation of
Draco, a nearby dwarf spheroidal galaxy. Of the approximately 35
robust X-ray source detections, we focus our attention on the
brightest of these sources, for which we report X-ray and
multiwavelength parameters. While most of the sources exhibit
properties consistent with active galactic nuclei, few of them possess
the characteristics of low-mass X-ray binaries (LMXBs) and cataclysmic
variable (CVs). Our analysis places constraints on the population of
X-ray sources with LX>3x1033erg/s in Draco, suggesting that there
are no actively accreting black hole and neutron star binaries.
However, we find four sources that could be quiescent state LMXBs/CVs
associated with Draco. We also place constraints on the central black
hole luminosity and on a dark matter decay signal around 3.5keV.
Description:
The 87ks image of Draco (Figure 1; RA=17:20:12.4 and DEC=+57:54:55.3
(J2000)) was obtained by the European Space Agency's (ESA) X-ray
Multi-Mirror Mission-Newton (XMM-Newton) between 2009 August 4 and 28
(PI: K. Dhuga).
We used the 3XMM-DR54 (3XMM) catalog (Rosen et al. 2015, IX/46) for
the automated multiwavelength (MW) classification described in Section
3.1. The parameters obtained from the 3XMM catalog are the source
coordinates and X-ray fluxes in four different energy bands.
The Hubble Space Telescope (HST) partly observed Draco with the WFPC2,
ACS/WFC, and WFC3/UVIS cameras between 2001 Aug 18 and 2013 Oct 14.
Objects:
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RA (ICRS) DE Designation(s)
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17 20 12.4 +57 54 55.3 Draco = NAME DRACO Dwarf Galaxy
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 150 35 Properties and automated results for classification
X-ray sources in the Draco field
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See also:
B/xmm : XMM-Newton Obs. Log (XMM-Newton Science Operation Center, 2012)
IX/46 : XMM-Newton Serendipitous Source Catalogue 3XMM-DR5 (XMM-SSC, 2016)
II/328 : AllWISE Data Release (Cutri+ 2013)
V/139 : The SDSS Photometric Catalog, Release 9 (Adelman-McCarthy+, 2012)
VII/258 : Quasars and Active Galactic Nuclei (13th Ed.) (Veron+ 2010)
V/136 : Teff and metallicities for Tycho-2 stars (Ammons+, 2006)
V/123 : Catalog of Cataclysmic Variables (Downes+ 2001-2006)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/ApJ/813/28 : Autoclassification of the variable 3XMM sources (Farrell+, 2015)
J/MNRAS/451/2735 : Four close dSph XXM observations (Manni+, 2015)
J/MNRAS/448/2717 : Resolved stellar spectra Bayesian analysis (Walker+, 2015)
J/AJ/149/42 : Proper motion of Draco dwarf galaxy from HST (Pryor+, 2015)
J/ApJ/756/27 : Classif. of sources from the 2XMMi-DR3 cat. (Lin+, 2012)
J/A+A/469/807 : Catalogue of Galactic low-mass X-ray binaries (Liu+, 2007)
J/MNRAS/375/831 : Draco MegaCam, INT and HST photometry (Segall+, 2007)
J/A+A/455/1165 : Catalogue of Galactic high-mass X-ray binaries (Liu+, 2006)
J/A+A/442/165 : IJKs photom. of late-type stars in Draco dSph (Cioni+, 2005)
J/ApJS/160/319 : COUP: observations and source lists (Getman+, 2005)
J/ApJS/145/245 : SDSS stars in Draco dwarf spheroidal galaxy (Rave+, 2003)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Seq Sequential Running number
4- 11 F8.4 deg RAdeg Right Ascension, decimal degrees (J2000)
13- 19 F7.4 deg DEdeg Declination, decimal degrees (J2000)
21- 24 F4.2 arcsec ePos [0.4/6.3] Positional Uncertainty
from 3XMM-DR5 catalog
26- 30 F5.1 10-14mW/m2 Flux [0.1/157] Observed X-ray flux in
the 0.5-12keV range
32- 36 F5.2 10-14mW/m2 e_Flux [0.3/16] Uncertainty in Flux
38- 42 F5.2 --- HR2 Hardness ratio (1)
44- 47 F4.2 --- e_HR2 [0.01/0.4] Uncertainty in HR2
49- 53 F5.2 --- HR4 Hardness ratio (1)
55- 58 F4.2 --- e_HR4 [0.01/0.9] Uncertainty in HR4
60- 64 F5.1 --- S/N [6/116] Signal-to-noise ratio
66- 70 F5.2 mag umag [10/29.2]? SDSS DR9 u magnitude
72- 76 F5.2 mag gmag [11.3/23.2]? SDSS DR9 g magnitude
78- 82 F5.2 mag rmag [11.4/22.5]? SDSS DR9 r magnitude
84- 88 F5.2 mag imag [11.3/23.2]? SDSS DR9 i magnitude
90- 94 F5.2 mag zmag [9.8/22.5]? SDSS DR9 z magnitude
96-100 F5.2 mag Jmag [7.7/16.7]? 2MASS J magnitude
102-106 F5.2 mag Hmag [7.4/16.5]? 2MASS H magnitude
108-112 F5.2 mag Ksmag [7.4/15.8]? 2MASS Ks magnitude
114-118 F5.2 mag W1mag [7.7/16.2]? WISE W1 magnitude (3.35um)
120-124 F5.2 mag W2mag [7.4/16.4]? WISE W2 magnitude (4.6um)
126-130 F5.2 mag W3mag [7.3/13]? WISE W3 magnitude (11.6um)
132-141 A10 --- Class Class
143-144 I2 --- Prob [84/99]? Probability for not being a
spurious detection (see section 3.2)
146-150 A5 --- Flag Object Flags (2)
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Note (1): HR2=(F1.2-2-F0.2-1.2)/(F1.2-2+F0.2-1.2) and
HR4=(F2-7-F0.5-2)/(F2-7+F0.5-2), where FX-Y is the
observed flux in the X-Y keV energy band, e.g., 1.2-2keV band.
Note (2): Object Flags as follows:
h = GM Dra, variable star in Tycho 2 (Hog et al. 2000, Cat. I/259)
i = A cool K9 type star with X-ray luminosity of 3.7x10^29erg/s at a
distance of ∼125pc; Ammons et al. 2006, Cat. V/136.
j = Visually resolved in the SDSS images.
k = Symbiotic star in Draco, Belczynski et al. 2000, J/A+AS/146/407.
l = Source 30 also shows complex morphology (likely, superposition of star
and galaxy as can be seen in Figure∼2.
m = Three sources have the uncertainties of fluxes in the individual bands
(1-2keV, 2-4.5keV, etc.) larger than the fluxes themselves, according
to 3XMM-DR5, which results in the large total flux uncertainty.
n = In these cases the uncertainty is strongly asymmetric, because the value
of HR hits the boundary; the maximum uncertainty is given in this table.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 23-Jun-2016