J/A+A/317/328 ROSAT PSPC survey of M 31 (Supper+ 1997)
ROSAT PSPC survey of M 31
Supper R., Hasinger G., Pietsch W., Truemper J., Jain A., Magnier E.A.
Lewin W.H.G., van Paradijs J.
<Astron. Astrophys. 317, 328 (1997)>
=1997A&A...317..328S 1997A&A...317..328S (SIMBAD/NED BibCode)
ADC_Keywords: Infrared sources ; X-ray sources
Mission_Name: ROSAT
Keywords: galaxies: fundamental parameters - galaxies: individual: M 31 -
galaxies: luminosity function - galaxies: spiral - X-rays: general
X-rays: stars
Description:
This paper reports on results of the analysis of the first M 31 survey
with the ROSAT PSPC performed in July 1991. Within the ≃ 6.3deg2
field of view we detected 396 individual X-ray sources with
(0.1keV-2.4keV) fluxes ranging from ≃ 5x10-15erg/cm2/s^ to
≃ 4x10-12erg/cm2/s. Of these 396 sources, 43 have be en
tentatively identified with foreground stars, 29 with globular
clusters, 17 with supernova remnants, 3 with other galaxies
(including M 32), and 3 with radio sources. A detailed analysis of the
integral flux distribution of the sources shows that approximately one
fifth are likely to be background objects. By comparison with the
results of the Einstein M 31 survey, we find 327 newly detected
sources, 15 moderately variable sources, 3 bright and 6 faint possible
transient sources. For those sources in M 31, the observed
luminosities range from ≃ 3x1035erg/s to ≃ 2x1038erg/s
(at 690kpc). The total (0.1keV-2.4keV) luminosity of M 31 is
(2.9±0.3)x1039erg/s, roughly one third of which is from the bulge
and two thirds of which are from the disk. The luminosity of a diffuse
component within the bulge region is estimated to be less than
3.2x1038erg/s. An explanation in terms of hot gaseous emission leads
to a maximum total gas mass of 1.7x106M☉. We find that the
integral luminosity distribution of sources associated with globular
clusters is similar to that of the Milky Way. Finally, the results of
spectral fits to 56 of the brightest sources are discussed; we
classify 15 objects as "supersoft sources" according to their spectral
characteristics.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5 104 396 List of all 396 ROSAT sources found in M31
table6 51 73 Correlation with the Einstein source catalog
table7 134 104 Correlations with different data bases
table8 142 56 Spectral fit parameters of 56 bright X-ray sources
table9 21 48 *Power law fit parameters with fixed NH
tables.tex 214 798 LaTeX (with supertabular) version of tables
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Note to table9: The photon collection circles are the same as in table8.
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Byte-by-byte Description of file: table5
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Bytes Format Units Label Explanations
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1- 3 A3 --- n_ROSAT Note on ROSAT source number (1)
5- 7 I3 --- ROSAT ROSAT source number
9 I1 h RAh Right ascension J2000
11- 12 I2 min RAm Right ascension J2000
14- 17 F4.1 s RAs Right ascension J2000
18 A1 --- DE- Declination sign
19- 20 I2 deg DEd Declination J2000
22- 23 I2 arcmin DEm Declination J2000
25- 26 I2 arcsec DEs Declination J2000
28- 29 I2 arcsec e_DEs 1 sigma position error
31 I1 --- Cl [1/3] Source classification (2)
33- 39 F7.1 --- MaxL Maximum likehood
41- 42 A2 --- Band Energy band with highest detection (3)
44 A1 --- l_rateB Limit flag on rate B (4)
45- 50 F6.2 ct/ks rateB Count rate in the B-band
52- 55 F4.2 ct/ks e_rateB ? rms uncertainty on rateB (5)
57 A1 --- l_rateS Limit flag on rate S (4)
58- 62 F5.2 ct/ks rateS Count rate in the S-band
64- 67 F4.2 ct/ks e_rateS ? rms uncertainty on rateS (5)
69 A1 --- l_rateH Limit flag on rate H (4)
70- 75 F6.2 ct/ks rateH Count rate in the H-band
77- 80 F4.2 ct/ks e_rateH ? rms uncertainty on rateH (5)
82 A1 --- l_rateH1 Limit flag on rate H1 (4)
83- 87 F5.2 ct/ks rateH1 Count rate in the H1-band
89- 92 F4.2 ct/ks e_rateH1 ? rms uncertainty on rateH1 (5)
94 A1 --- l_rateH2 Limit flag on rate H2 (4)
95- 99 F5.2 ct/ks rateH2 Count rate in the H2-band
101-104 F4.2 ct/ks e_rateH2 ? rms uncertainty on rateH2 (5)
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Note (1): a: Galactic foreground star
b: Background galaxy
c: Radio source
d: Globular cluster
e: SNR
*: bulge source
+: Sources with uncertain count rate
Note (2): The X-ray sources are classified due to the quality of their
detection, which has an influence on the determined properties:
1 = best, 2 = medium, 3 = moderate.
Note (3): The ROSAT energy bands are coded within this paper as:
B = Broad = 0.1-2.4 keV
S = Soft = 0.1-0.4 keV
H1 = Hard1 = 0.5-0.9 keV
H2 = Hard2 = 0.9-2.0 keV
H = Hard = 0.5-2.0 keV (= H1 + H2).
Note (4): For sources not detected in a considered energy band 1σ upper
limits have been calculated indicated by a `<`-symbol in front of
the upper limit value.
Note (5): The listed count rate errors are only statistical. The systematic
errors are expected to be less than ∼15%.
A conversion of count rates into fluxes depends on the assumed
spectral shape. For M31-sources a power law with Γ=-2.0 and
NH=9x1020cm-2 may be used, leading to the conversion factor
1cts/ks=3.12x10-14erg/cm2/s in the 0.1-2.4keV band
(B-band). For foreground stars the application of this conversion
factor leads to an over-estimate of the fluxes.
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Byte-by-byte Description of file: table6
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Bytes Format Units Label Explanations
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1 A1 --- n_ROSAT [*] Note on ROSAT source number (1)
2- 4 I3 --- ROSAT ROSAT source number
6- 10 F5.2 0.1fW/m2 FR Source flux measured by ROSAT (2)
12- 15 F4.2 0.1fW/m2 e_FR rms uncertainty on FR
17- 19 I3 --- Einst. Einstein source number
21- 25 F5.2 0.1fW/m2 FE Source flux measured by Einstein (2)
27- 30 F4.2 0.1fW/m2 e_FE ? rms uncertainty on FE
32- 35 F4.1 arcsec Dist Distance between sources
37- 40 F4.2 --- Dists Distance between sources in sigma (3)
42- 46 F5.2 --- FR/FE ROSAT-Eintein source flux ratio
48- 51 F4.2 --- e_FR/FE ? rms uncertainty on FR/FE (4)
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Note (1): ROSAT source numbers marked with a star are bulge sources for which
the fluxes and variabilities could be overestimated.
Note (2): Source flux obtained by applying the spectral model of TF (thermal
bremsstrahlung with kT=5keV and NH=7x1020cm-2) in the
0.2-4.0keV energy band.
Note (3): Expressed in sigma of their combined 1 sigma position error.
Note (4): Gaussian error propagation used.
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Byte-by-byte Description of file: table7
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Bytes Format Units Label Explanations
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1- 3 I3 --- ROSAT ? ROSAT source number
5- 21 A17 --- DataBase Data base with correlations (1)
23- 26 F4.1 arcsec Dist1 Distance between sources in arcsec
29- 32 F4.1 arcsec Dist2 ? Distance between sources in arcsec (2)
35- 38 F4.1 arcsec Dist3 ? Distance between sources in arcsec (2)
40- 43 F4.2 --- Dist1s Distance 1 between sources in sigma (3)
46- 49 F4.2 --- Dist2s ? Distance 2 between sources in sigma (3)
52- 55 F4.2 --- Dist3s ? Distance 3 between sources in sigma (3)
57- 86 A30 --- Id Identification
88-102 A15 --- Type Type (star, galaxy, SNR, cluster)
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Note (1): For a detailed description of the used data bases see printed paper.
Here a short listing:
BA87, BA93 = Globular cluster lists of
Battistini et al. (1987A&AS...67..447B 1987A&AS...67..447B)
Battistini et al. (1993A&A...272...77B 1993A&A...272...77B)
BW93 = SNR-list of Braun & Walterbos (1993A&AS...98..327B 1993A&AS...98..327B)
DO80 = SNR-list of d'Odorico et al. (1980A&AS...40...67D 1980A&AS...40...67D)
MA92 = Foreground star catalogs by
Magnier et al. (1992A&AS...96..379M 1992A&AS...96..379M)
Haiman et al. (1994A&A...286..725H 1994A&A...286..725H)
MA94b = SNR-list of Magnier et al., 1994, A&AS, submitted
NED = NASA Extragalactic Database (Version 30.Dec.1992)
SIMBAD = SIMBAD catalog (Centre de Donnees astronomiques de
Strasbourg, Version Dec.1989)
Note (2): When more than one data base are listed in Data_Base
Note (3): Expressed in sigma of their combined 1 sigma position error.
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Byte-by-byte Description of file: table8
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Bytes Format Units Label Explanations
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1- 2 A2 --- n_ROSAT Note on ROSAT source number (1)
3- 5 I3 --- ROSAT ROSAT source number
7- 9 F3.1 --- Circle Photon collection circle (2)
11- 14 I4 --- Counts Number of photons used for the fit
16- 21 F6.2 10+20cm-2 NH1 ? Hydrogen abs. column density for Gamma
23- 28 F6.2 10+20cm-2 E_NH1 ? Error in NH1 (upper limit)
30- 35 F6.2 10+20cm-2 e_NH1 ? Error in NH1 (lower limit)
37- 41 F5.2 --- Gamma ? Power law index
43- 46 F4.2 --- E_Gamma ? Error in Gamma (upper limit)
48- 52 F5.2 --- e_Gamma ? Error in Gamma (lower limit)
54- 57 F4.2 --- 2_Gamma ? Reduced Chi2 for Gamma
59- 63 F5.2 10+20cm-2 NH2 ? Hydrogen absolute column density for
Thermal Bremsstrahlung fit
65- 70 F6.2 10+20cm-2 E_NH2 ? Error in NH2 (upper limit)
72- 76 F5.2 10+20cm-2 e_NH2 ? Error in NH2 (lower limit)
78- 81 F4.2 keV kT1 ? Thermal Bremsstrahlung temperature
83- 87 F5.2 keV E_kT1 ? Error in kT1 (upper limit)
89- 92 F4.2 keV e_kT1 ? Error in kT1 (lower limit)
94- 97 F4.2 --- 2_kT1 ? Reduced Chi2 for kT1
99 A1 --- Fit [BT] Spectral fit model indicator (3)
B: Black body; T: Thermal plasma
101-105 F5.2 10+20cm-2 NH3 ? Hydrogen column density for Fit
107-112 F6.2 10+20cm-2 E_NH3 ? Error in NH3 (upper limit)
114-118 F5.2 10+20cm-2 e_NH3 ? Error in NH3 (lower limit)
120-124 F5.2 keV kT2 ? Thermal Plasma/Blackbody temperature
126-131 F6.2 keV E_kT2 ? Error in kT2 (upper limit)
133-137 F5.2 keV e_kT2 ? Error in kT2 (lower limit)
139-142 F4.2 --- 2_Fit ? Reduced Chi2 for Fit
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Note (1): a: Galactic foreground star
b: Background galaxy
d: Globular cluster
e: SNR
*: bulge source
Note (2): Expressed in sigma of the point spread function of the intrumentation
ROSAT XRT+PSPC.
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Byte-by-byte Description of file: table9
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Bytes Format Units Label Explanations
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1- 2 A2 --- n_ROSAT Note on ROSAT source number (1)
3- 5 I3 --- ROSAT ROSAT source number
7- 11 F5.2 --- Gamma Power law index
13- 16 F4.2 --- e_Gamma rms uncertainty on Gamma
18- 21 F4.2 --- 2_Gamma Reduced Chi2 for Gamma
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Note (1): d: Globular cluster
e: SNR
*: bulge source
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(End) Patricia Bauer [CDS] 22-Apr-1996