J/MNRAS/399/728 UV-bright sources behind M31 halo (Fittingoff+, 2009)
A survey of ultraviolet-bright sources behind the halo of M31.
Fittingoff A., Prochaska J.X., Kalirai J.S., Strader J., Guhathakurta P.,
Kaplan K.F.
<Mon. Not. R. Astron. Soc., 399, 728-736 (2009)>
=2009MNRAS.399..728F 2009MNRAS.399..728F
ADC_Keywords: Galaxies, nearby ; Ultraviolet ; QSOs
Keywords: galaxies: haloes - galaxies: individual: M31 -
quasars: absorption lines
Abstract:
We have performed a wide-area ultraviolet (UV) imaging survey using
the GALaxy Evolution eXplorer to search for bright, point-like UV
sources behind M31's extended halo. Our survey consisted of 46
pointings covering an effective area of ∼50deg2, in both the far-UV
and near-UV channels. We combined these data with optical R-band
observations acquired with the WIYN Mosaic-1 imager on the Kitt Peak
National Observatory 0.9-m WIYN telescope. An analysis of the
brightness and colours of sources matched between our photometric
catalogues yielded ∼100 UV-bright quasar candidates. We have
obtained discovery spectra for 76 of these targets with the Kast
spectrometer on the Lick 3-m telescope and confirmed 30 active
galactic nuclei and quasars, 29 galaxies at z>0.02 including several
early-type systems, 16 Galactic stars (hot main-sequence stars) and
one featureless source previously identified as a BL Lac object.
Future UV spectroscopy of the brightest targets with the Cosmic
Origins Spectrograph on the Hubble Space Telescope will enable a
systematic search for diffuse gas in the extended halo of M31.
Description:
We were awarded a total of 46 pointings during Cycle 2 (PI: Prochaska;
ID=033) of the GALEX mission to image a portion of M31's outer halo.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 97 98628 Photometry summary of GALEX/NUV-detected sources
in the halo of M31.
table4.dat 65 75 Lick/KAST spectroscopy of QSO candidates
table5.dat 57 60 UV bright, extragalactic sources behind M31
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See also:
J/ApJS/173/643 : GALEX UV photometry of M31 Globular Clusters (Rey+, 2007)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Seq Sequential number
7- 11 A5 --- --- [GALEX]
13- 31 A19 --- GALEX GALEX name (JHHMMSS.ss+DDMMSS.s),
<[FPK2009] GALEX JHHMMSS.ss+DDMMSS.s> in Simbad
33- 34 I2 h RAh GALEX right ascension (J2000)
36- 37 I2 min RAm GALEX right ascension (J2000)
39- 43 F5.2 s RAs GALEX right ascension (J2000)
45 A1 --- DE- Declination sign (J2000)
46- 47 I2 deg DEd Declination (J2000)
49- 50 I2 arcmin DEm Declination (J2000)
52- 56 F5.2 arcsec DEs Declination (J2000)
57- 61 F5.2 mag FUV ?=99.99 GALEX/FUV far-UV magnitude (1)
63- 67 F5.2 mag e_FUV ?=-1.00 rms uncertainty on FUV (1)
69- 73 F5.2 mag NUV ?=99.99 GALEX/NUV near-UV magnitude (2)
75- 78 F4.2 mag e_NUV ?=-1.00 rms uncertainty on NUV (2)
80- 84 F5.2 mag Rmag ?=99.99 R magnitude from KPNO photometry (3)
86- 90 F5.2 mag e_Rmag ? rms uncertainty on Rmag
92- 95 F4.2 --- s/g Star/galaxy classifier calculated by
SExtractor on the NUV photometry (4)
97 A1 --- Q? [Y/N] Quasar candidates picked based on
colour relations between UV and R (5)
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Note (1): NUV extractions with no FUV match have FUV values of 99.99
and an error of -1. GALEX magnitudes are in AB system
Note (2): For NUV extractions where KPNO imaging exists but no source was
detected, we report a value of 99.99. For NUV extractions where no
KPNO imaging exists, we report no values.
Note (3): R-band magnitudes from KPNO photometry are reported for the NUV
extraction that are matched to within a 2 arcsec radius of a KPNO
source.
Note (4): Values near unity indicate a stellar-like PSF
Note (5): The criteria used were 0.5 <FUV-NUV<2, NUV-R<2 and NUV<21.
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name Name (JHHMMSS+DDMMSS),
<[FPK2009] JHHMMSS+DDMMSS> in Simbad
16- 17 I2 h RAh GALEX right ascension (J2000)
19- 20 I2 min RAm GALEX right ascension (J2000)
22- 23 I2 s RAs GALEX right ascension (J2000)
25 A1 --- DE- Declination sign (J2000)
26- 27 I2 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 33 I2 arcsec DEs Declination (J2000)
35- 44 A10 "DD/MM/YYYY" Date Observation date
46- 49 I4 s expT Exposure time
51- 60 A10 "DD/MM/YYYY" Date2 Second observation date
62- 65 I4 s expT2 ? Exposure time for second observation
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1 A1 --- Type [AG] AGN (BAL) or Galaxy (NEL) (1)
3- 16 A14 --- Name Name (JHHMMSS+DDMMSS),
<[FPK2009] JHHMMSS+DDMMSS> in Simbad
18- 19 I2 h RAh GALEX right ascension (J2000)
21- 22 I2 min RAm GALEX right ascension (J2000)
24- 25 I2 s RAs GALEX right ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 35 I2 arcsec DEs Declination (J2000)
37- 39 I3 kpc rho Impact parameter from the centre of M31 (2)
41- 45 F5.2 mag FUV ?=99.99 Far UV magnitude (in AB system)
47- 51 F5.2 mag NUV ?=99.99 Narrow UV magnitude (in AB system)
53- 57 F5.3 --- z Redshift
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Note (1): Type as follows:
A = AGN (broad emission lines)
G = Galaxies (narrow emission lines)
Note (2): Impact parameter from the centre of M31, taken to be
00:42:44.3+41:16:09 (J2000), for an assumed distance of 783kpc.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 02-Aug-2010