J/ApJ/771/13 UV-IR photometry of SMC stars (Lepo+, 2013)
A search for rapidly accreting white dwarfs in the Small Magellanic Cloud.
Lepo K., van Kerkwijk M.
<Astrophys. J., 771, 13 (2013)>
=2013ApJ...771...13L 2013ApJ...771...13L
ADC_Keywords: Magellanic Clouds ; Photometry, UBV ; Photometry, ultraviolet ;
Photometry, infrared
Keywords: novae, cataclysmic variables; supernovae: general; ultraviolet: stars
Abstract:
The nature of the progenitors of Type Ia supernovae (SNe Ia) is
still a mystery. While plausible candidates are known for both the
single-degenerate and double-degenerate models, the observed numbers
fall significantly short of what is required to reproduce the SNe Ia
rate. Some of the most promising single-degenerate Type Ia progenitors
are recurrent novae and super-soft sources (SSS). White dwarfs (WDs)
with higher mass transfer rates can also be SN Ia progenitors. For
these rapidly accreting white dwarfs (RAWDs), more material than is
needed for steady burning accretes on the WD, and extends the WD's
photosphere. Unlike SSS, such objects will likely not be detectable at
soft X-ray energies, but will be bright at longer wavelengths, such as
the far-ultraviolet (UV). Possible examples include LMC N66 and the
V Sagittae stars. We present a survey using multi-object spectrographs
looking for RAWDs in the central core of the Small Magellanic Cloud
(SMC), from objects selected to be bright in the far-UV and with blue
far UV-V colors. While we find some unusual objects, and recover known
planetary nebula and Wolf-Rayet (WR) stars, we detect no candidate
RAWD. The upper limits from this non-detection depend on our
expectations of what an RAWD should look like, as well assumptions
about the internal extinction of the SMC. Assuming they resemble LMC
N66 or fainter versions of WR stars we set an upper limit of 10-14
RAWDs in the SMC. However, our survey is unlikely to detect objects
like V Sge, and hence we cannot set meaningful upper limits if RAWDs
generally resemble V Sge.
Description:
The Magellanic Clouds were surveyed by the Ultraviolet Imaging
Telescope (UIT) during two space shuttle missions in late 1990 and
early 1995, using several FUV filters, including B5 at 162nm (Cornett
et al. 1997, J/AJ/113/1011). Since the UIT observations cover the
entire central bar of the SMC, while the LMC observations are in
scattered fields, we chose to use the SMC data to simplify followup
observations.
We matched objects in the UIT SMC catalog with the optical Magellanic
Cloud Photometric Survey (MCPS; Zaritsky et al. 2002, J/AJ/123/855).
We took optical spectra of a majority of the objects outside of the
main-sequence clump of Figure 1, using the multi-object spectrometers
FLAMES on the Very Large Telescope and AAOmega on the Anglo-Australian
Telescope. In the end, we had 503 unique objects and 745 spectra taken
from 2010 October to 2011 January.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 172 6609 Combined UIT (Cornett et al. 1997, J/AJ/113/1011)
and MCPS (Zaritsky et al. 2002, J/AJ/123/855)
catalog
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
VI/104 : The Ultraviolet Imaging Telescope (UIT) (1990, 1995)
J/ApJ/745/173 : UV absorption sight lines of LMC and SMC (Welty+, 2012)
J/ApJS/187/275 : Photometric histories of recurrent novae (Schaefer, 2010)
J/PASP/121/634 : FUSE observations in Magellanic Clouds (Blair+, 2009)
J/ApJ/700/844 : Rotation rates of very massive stars (Penny+, 2009)
J/AJ/127/1632 : UBVR(UIT) photometry of O and OB stars in SMC (Oey+, 2004)
J/AJ/123/855 : Magellanic Clouds Photometric Survey: SMC (Zaritsky+, 2002)
J/AJ/116/180 : Magellanic clouds ultraviolet observations (Parker+ 1998)
J/AJ/113/1011 : UV Observations of the SMC (Cornett+ 1997)
J/ApJ/425/122 : IMF from UV stellar photometry (Hill+, 1994)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 15 A15 --- Name USS catalog name
17- 24 F8.5 deg RAOdeg Original UIT Right Ascension J2000
26- 34 F9.5 deg DEOdeg Original UIT Declination J2000
36- 43 F8.5 deg RAUdeg Revised UIT Right Ascension J2000 (1)
45- 53 F9.5 deg DEUdeg Revised UIT Declination J2000 (1)
55- 59 F5.2 mag m162 [9.3/16.7] UIT 162nm-band magnitude
61- 64 F4.2 mag e_m162 [0.02/0.6] Error in m162
66- 67 A2 --- Field UIT SMC field (f1, f2, f3 or f4)
69- 76 F8.5 deg RAdeg MCPS Right Ascension J2000 (2)
78- 86 F9.5 deg DEdeg MCPS Declination J2000 (2)
88- 92 F5.2 mag Umag ? MCPS U magnitude
94- 98 F5.2 mag e_Umag ? Error in Umag
100-104 F5.2 mag Bmag ? MCPS B magnitude
106-109 F4.2 mag e_Bmag ? Error in Bmag
111-115 F5.2 mag Vmag [10.4/21.4]? MCPS V magnitude
117-120 F4.2 mag e_Vmag [0.01/0.6]? Error in Vmag
122-126 F5.2 mag Imag ? MCPS I magnitude
128-131 F4.2 mag e_Imag ? Error in Imag
133-137 F5.2 mag Jmag ? 2MASS J magnitude
139-143 F5.2 mag e_Jmag ? Error in Jmag
145-149 F5.2 mag Hmag ? 2MASS H magnitude
151-155 F5.2 mag e_Hmag ? Error in Hmag
157-161 F5.2 mag Ksmag [5.7/16.2]? 2MASS Ks magnitude
163-167 F5.2 mag e_Ksmag [0.03/10]? Error in Ksmag
169-172 F4.2 arcsec Sep [0.02/3] Separation between revised UIT and
MCPS positions
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Note (1): The SMC was surveyed by the Ultraviolet Imaging Telescope (UIT)
during two space shuttle missions in late 1990 and early 1995, using
several FUV filters, including B5 at 162nm (Cornett et al. 1997,
J/AJ/113/1011).
Note (2): MCPS = the optical Magellanic Cloud Photometric Survey (Zaritsky
et al. 2002, J/AJ/123/855; in Simbad).
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 15-Jan-2015