J/ApJ/841/33 AGB stars with GALEX observations (Montez+, 2017)
A catalog of GALEX ultraviolet emission from asymptotic giant branch stars.
Montez R., Ramstedt S., Kastner J.H., Vlemmings W., Sanchez E.
<Astrophys. J., 841, 33 (2017)>
=2017ApJ...841...33M 2017ApJ...841...33M
ADC_Keywords: Stars, giant ; Stars, carbon ; Photometry, ultraviolet ;
Photometry, RI
Keywords: binaries: general ; stars: AGB and post-AGB ; stars: chromospheres ;
ultraviolet: stars
Abstract:
We have performed a comprehensive study of the UV emission detected
from asymptotic giant branch (AGB) stars by the Galaxy Evolution
Explorer (GALEX). Of the 468 AGB stars in our sample, 316 were
observed by GALEX. In the near-UV (NUV) bandpass (λeff∼2310Å),
179 AGB stars were detected and 137 were not detected. Only 38 AGB
stars were detected in the far-UV (FUV) bandpass (λeff∼1528Å).
We find that NUV emission is correlated with optical to near-infrared
emission, leading to higher detection fractions among the brightest,
and hence closest, AGB stars. Comparing the AGB time-variable visible
phased light curves to corresponding GALEX NUV phased light curves, we
find evidence that for some AGB stars the NUV emission varies in phase
with the visible light curves. We also find evidence that the NUV
emission and possibly the FUV emission are anticorrelated with the
circumstellar envelope density. These results suggest that the origin
of the GALEX-detected UV emission is an inherent characteristic of the
AGB stars that can most likely be traced to a combination of
photospheric and chromospheric emission. In most cases, UV detections
of AGB stars are not likely to be indicative of the presence of binary
companions.
Description:
Our sample of AGB stars is derived from numerous AGB samples found in
the literature and was originally compiled by Ramstedt+
(2012A&A...543A.147R 2012A&A...543A.147R) to search for X-ray detections associated with
AGB stars.
The GALEX mission performed a two-band survey of the UV sky. Using a
dichromatic beam splitter, GALEX simultaneously observed far-UV (FUV;
λeff∼1528Å; 1344-1786Å) and near-UV (NUV;
λeff∼2310Å; 1771-2831Å) in surveys with different depths.
The spatial resolution is 4.3" in FUV and 5.3" in NUV.
As described in further detail in Morrissey+ (2007ApJS..173..682M 2007ApJS..173..682M),
spectroscopic observations place a grism into the converging beam of
the telescope to simultaneously disperse all sources onto the detector
plane. According to Morrissey+ (2007), the usable ranges of the grism
spectra are 1300-1820Å and 1820-3000Å in the FUV and NUV, with
average resolutions of 8Å and 20Å, respectively.
To supplement our study of the GALEX observations of AGB stars, we
collected photometric data from across the electromagnetic spectrum
for all the AGB stars considered using SIMBAD and VizieR tools.
We aslo collected AAVSO light curves that span the GALEX mission
lifetime (2003 May 28 to 2013 June 28) from the AAVSO International
Database.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 103 286 Catalog of AGB stars associated with GALEX sources
table2.dat 72 137 Limiting magnitudes for undetected AGB stars with
GALEX observations
table4.dat 55 10 AGB stars with GALEX grism spectroscopy
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See also:
B/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
II/312 : GALEX-DR5 (GR5) sources from AIS and MIS (Bianchi+ 2011)
J/A+A/324/1059 : C-rich stars IR and UBVRI photometry (Le Bertre 1997)
J/A+A/382/184 : Crystalline silicates around evolved stars (Molster+, 2002)
J/MNRAS/369/751 : Near-infrared photometry of carbon stars (Whitelock+, 2006)
J/A+A/498/627 : Radial velocities of SB with M giant (Famaey+, 2009)
J/MNRAS/411/2770 : Hot white dwarfs in GALEX-DR5 (Bianchi+, 2011)
J/MNRAS/414/418 : Chromospheric Mg II h+k flux of evolved stars (Perez+, 2011)
J/ApJ/728/149 : Polarized SiO masers of VX Sgr (Vlemmings+, 2011)
J/AJ/143/28 : Analysis of B6-A9 stars from INES UV spectra (Freire+, 2012)
J/ApJS/227/6 : LCs re-analysis of Mira variables in ASAS (Vogt+, 2016)
http://galex.stsci.edu/ : GALEX Public Archive on MAST
http://www.galex.caltech.edu/ : GALEX home page
http://www.aavso.org/ : AAVSO International Database
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Object identifier
11- 19 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
21- 29 F9.5 deg DEdeg Declination in decimal degrees (J2000)
31 A1 --- Type Chemical type
33- 37 F5.2 mag Vmag [3.9/13.1]? Apparent V band magnitude
39- 43 F5.2 mag Jmag [-2.7/5.1]? Apparent J band magnitude
45- 48 F4.2 mag E(B-V) [0.01/3.5] Extinction estimate
50- 52 A3 --- Survey GALEX survey mode (1)
54- 63 A10 "Y/M/D" Date UT date of the observation
65- 69 I5 s Nexp [37/27576]? NUV exposure time
71- 75 F5.2 mag NUVmag [12.9/24]? GALEX NUV band apparent AB magnitude
77- 80 F4.2 mag e_NUVmag [0/0.7]? Uncertainty in NUVmag
82- 86 I5 s Fexp [28/11032]? FUV exposure time
88 A1 --- l_FUVmag Limit flag on FUVmag
89- 93 F5.2 mag FUVmag [15.2/24]? GALEX FUV band apparent AB magnitude
95- 98 F4.2 mag e_FUVmag [0/3]? Uncertainty in FUVmag
100-103 F4.2 arcsec OffSet [0.1/2.5]? Offset between GALEX and AGB star
positions
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Note (1): GALEX survey as follows:
AIS = All-Sky Imaging Survey (AIS); typical exposure of ∼150s (191 occurrences)
MIS = Medium Imaging Survey (MIS); typical exposure of ∼1500s (37 occurrences)
GII = Final "GII" (39 occurrences)
DIS = Deep Imaging Survey (15 occurrences)
NGS = Nearby Galaxy Survey (4 occurrences)
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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- 10 A10 --- Name Object identifier
12- 20 F9.5 deg RAdeg Right Ascension in decimal degrees (J2000)
22- 30 F9.5 deg DEdeg Declination in decimal degrees (J2000)
32 A1 --- Type Chemical type
34- 38 F5.2 mag Vmag [5.2/20]? Apparent V band magnitude
40- 43 F4.2 mag Jmag [1/8.2]? Apparent J band magnitude
45- 48 F4.2 mag E(B-V) [0.01/3] Extinction estimate
50- 54 I5 s Nexp [44/22828] NUV exposure time
56 A1 --- l_NUVmag Limit flag on NUVmag
57- 60 F4.1 mag NUVmag [20.4/23.2] GALEX NUV band apparent AB magnitude
62- 66 I5 s Fexp [43/29876]? FUV exposure time
68 A1 --- l_FUVmag Limit flag on FUVmag
69- 72 F4.1 mag FUVmag [20/23.2]? GALEX FUV band apparent AB magnitude
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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- 10 A10 --- Name Object identifier
12- 18 A7 --- OName Other name
20- 30 A11 "Y/M/D" Date UT date of observation
32- 36 I5 s tNUV [1088/11325] NUV exposure time
38- 42 I5 s tFUV [1007/11325] FUV exposure time
44- 55 A12 --- Det Detected
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 15-Jan-2018