J/A+A/550/A18 XMM X-ray sources in Fornax dwarf galaxy (Nucita+, 2013)
An XMM-Newton search for X-ray sources in the Fornax dwarf galaxy.
Nucita A.A., Manni L., De Paolis F., Vetrugno D., Ingrosso G.
<Astron. Astrophys., 550, A18 (2013)>
=2013A&A...550A..18N 2013A&A...550A..18N
ADC_Keywords: Galaxies, nearby ; X-ray sources
Keywords: X-rays: individuals: Fornax dSph - black hole physics
Abstract:
We report the results of a deep archive XMM-Newton observation of the
Fornax spheroidal galaxy that we analyzed with the aim of fully
characterizing the X-ray source population (in most of the cases
likely to be background active galactic nuclei) detected towards the
target. A cross correlation with the available databases allowed us to
find a source that may be associated with a variable star belonging to
the galaxy. We also searched for X-ray sources in the vicinity of the
Fornax globular clusters GC 3 and GC 4 and found two sources probably
associated with the respective clusters. The deep X-ray observation
was also suitable for the search of the intermediate-mass black hole
(of mass~=104M☉) expected to be hosted in the center of the
galaxy. In the case of Fornax, this search is extremely difficult
since the galaxy centroid of gravity is poorly constrained because of
the large asymmetry observed in the optical surface brightness. Since
we cannot firmly establish the existence of an X-ray counterpart of
the putative black hole, we put constraints only on the accretion
parameters. In particular, we found that the corresponding upper limit
on the accretion efficiency, with respect to the Eddington luminosity,
is as low as a few 10-5.
Description:
The Fornax dwarf galaxy (at J2000 coordinates RA=02:39:593 and
DE=-34:26:57.1) was observed on August 8, 2005 for ~=100ks
(Observation ID 0302500101) with the three European Photon Imaging
Cameras (EPIC MOS 1, MOS 2, and pn) on board the XMM-Newton satellite.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 74 107 The X-ray sources detected by our analysis
towards the Fornax dSph
table2.dat 48 19 List of the detected X-ray sources
cross-correlated with the catalog GMD093
(Gizis et al., 1993PASP..105..871G 1993PASP..105..871G)
table3.dat 47 13 *A few sources of the X-ray sample detected towards
the Fornax dSph correlated with the 2MASS catalog
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Note on table3.dat: Following Haakonsen & Rutledge (2009, Cat. J/ApJS/184/138),
we can try to constrain the nature of the sources by using the X-ray
(in the 0.2-2.4keV band) and NIR (J and K bands) fluxes
(see text and Fig. 3 for details).
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See also:
B/xmm : XMM-Newton Observation Log (XMM-Newton SOC, 2013)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/544/A73 : BVI photometry of Fornax dSph galaxy (de Boer+, 2012)
J/AJ/131/912 : BR photometry of Fornax dSph center (Olszewski+, 2006)
J/AJ/131/2114 : Radial velocities in Fornax dSph (Walker+, 2006)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Src [1/107] Source number
4- 5 A2 --- n_Src [*VM ] Notes on source (1)
7 A1 --- N [A-G] Label indicating which EPIC camera(s)
identified the source (2)
9 I1 h RAh Right ascension (J2000)
11- 12 I2 min RAm Right ascension (J2000)
14- 17 F4.1 s RAs Right ascension (J2000)
19 A1 --- DE- Declination sign (J2000)
20- 21 I2 deg DEd Declination (J2000)
23- 24 I2 arcmin DEm Declination (J2000)
26- 29 F4.1 arcsec DEs [0/60] Declination (J2000)
31- 33 F3.1 arcsec ePos Error on position
35- 39 F5.2 --- HR1 Hardness ratio 1, HR1=(H-M)/(S+M+H) (3)
41- 44 F4.2 --- e_HR1 rms uncertainty on HR1
46- 50 F5.2 --- HR2 Hardness ratio 2, HR1=(M-S)/(S+M+H) (3)
52- 55 F4.2 --- e_HR2 rms uncertainty on HR2
57- 61 F5.2 10-17W/m2 FX Minimum absorbed flux in 0.2-12keV band
63- 66 F4.2 10-17W/m2 e_FX rms uncertainty on FX
68- 70 F3.1 arcsec r2M ? Distance to 2MASS source (Cat. II/246)
72- 74 F3.1 arcsec rUB ? Distance to USNO-B1 source (Cat. I/284)
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Note (1): Notes as follows:
* = Means that the source is possibly associated (within 1σ) with a
counterpart found in the position and proper motions extended catalog
(PPMX, see Roeser et al. 2008, Cat. I/312), thus implying a possible
foreground source
V = When correlating the X-ray sources with the available catalogs, we found
that source number 61 is possibly associated, within 2.0", to one
(J023941.4-343340) belonging to a catalog of variable stars
(Bersier & Wood 2002, Cat. J/AJ/123/840), see text for details.
M = The X-ray source labeled as 107 also correlates (within 1.0") with a
source in the 2MASX (Skrutskie et al. 2006, Cat. VII/233) and is
possibly associated to a background AGN (QJ0240-3437, see also
Mendez et al. (2012AJ....143...93R 2012AJ....143...93R) where this quasar has been
considered as a reference object for measuring the proper motion of
sources belonging to the Fornax dSph). As a consequence, source 107
may have been erroneously reported in the PPMX catalog (source labeled
as 024019.0-343719).
Note (2): EPIC camera labels are:
A = pn only
B = pn and MOS 1
C = pn and MOS 2
D = pn, MOS 1, and MOS 2
E = MOS 1 and MOS 2
F = MOS 1
G = MOS 2
Note (3): S=0.3-1keV, M=1-4keV and H=4-10keV bands count rates.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- [GMD93] [1/19] Gizis et al. number
(1993PASP..105..871G 1993PASP..105..871G) (1)
4 I1 h RAh Right ascension (J2000)
6- 7 I2 min RAm Right ascension (J2000)
9- 12 F4.1 s RAs Right ascension (J2000)
14 A1 --- DE- Declination sign (J2000)
15- 16 I2 deg DEd Declination (J2000)
18- 19 I2 arcmin DEm Declination (J2000)
21- 24 F4.1 arcsec DEs Declination (J2000)
26- 28 I3 --- Src [1/107]? X-ray Src number (1)
30- 31 I2 arcsec Dist ? Distance between [GMD93] and Src sources
33- 34 I2 arcsec e_Dist ? rms uncertainty on Dist
36- 42 A7 --- Type Morphological type
44- 48 A5 --- Ref References (2)
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Note (1): The GMD093 sources labeled as 2, 9, 14, 17, 18, and 19
are out of the XMM-Newton FOV.
Note (2): References as follows:
1 = Tinney (1999MNRAS.303..565T 1999MNRAS.303..565T)
2 = Veron-Cetty & Veron (2006A&A...455..773V 2006A&A...455..773V, Cat. VII/248)
3 = Tinney et al. (1997MNRAS.285..111T 1997MNRAS.285..111T)
4 = Jones et al. (2006MNRAS.369...25J 2006MNRAS.369...25J)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Src [1/107]Src number
5- 8 F4.2 10-17W/m2 FX X-ray flux in 0.2-2.4keV band
10- 13 F4.2 10-17W/m2 e_FX rms uncertainty on FX
15- 20 F6.2 10-16W/m2 FJ 2MASS J-band flux
22- 25 F4.2 10-16W/m2 e_FJ rms uncertainty on FJ
27- 31 F5.2 mag Jmag 2MASS J magnitude
33- 36 F4.2 mag e_Jmag rms uncertainty on Jmag
38- 42 F5.2 mag Kmag 2MASS Ks magnitude
44- 47 F4.2 mag e_Kmag rms uncertainty on Kmag
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Apr-2013