J/ApJ/787/29 UVOT photometry of Super-Chandrasekhar mass SNe Ia (Brown+, 2014)
Ultraviolet observations of Super-Chandrasekhar mass Type Ia supernova
candidates with Swift UVOT.
Brown P.J., Kuin P., Scalzo R., Smitka M.T., De Pasquale M., Holland S.,
Krisciunas K., Milne P., Wang L.
<Astrophys. J., 787, 29 (2014)>
=2014ApJ...787...29B 2014ApJ...787...29B (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, ultraviolet
Keywords: supernovae: general -
supernovae: individual: SN 2009dc, SN 2011aa, SN 2012dn -
ultraviolet: general
Abstract:
Among Type Ia supernovae (SNe Ia), a class of overluminous objects
exist whose ejecta mass is inferred to be larger than the canonical
Chandrasekhar mass. We present and discuss the UV/optical photometric
light curves, colors, absolute magnitudes, and spectra of three
candidate Super-Chandrasekhar mass SNe - 2009dc, 2011aa, and
2012dn - observed with the Swift Ultraviolet/Optical Telescope. The
light curves are at the broad end for SNe Ia, with the light curves of
SN 2011aa being among the broadest ever observed. We find all three to
have very blue colors which may provide a means of excluding these
overluminous SNe from cosmological analysis, though there is some
overlap with the bluest of "normal" SNe Ia. All three are overluminous
in their UV absolute magnitudes compared to normal and broad SNe Ia,
but SNe 2011aa and 2012dn are not optically overluminous compared to
normal SNe Ia. The integrated luminosity curves of SNe 2011aa and
2012dn in the UVOT range (1600-6000 Å) are only half as bright as
SN 2009dc, implying a smaller 56Ni yield. While it is not enough to
strongly affect the bolometric flux, the early time mid-UV flux makes
a significant contribution at early times. The strong spectral
features in the mid-UV spectra of SNe 2009dc and 2012dn suggest a
higher temperature and lower opacity to be the cause of the UV excess
rather than a hot, smooth blackbody from shock interaction. Further
work is needed to determine the ejecta and 56Ni masses of SNe 2011aa
and 2012dn and to fully explain their high UV luminosities.
Description:
SC SNe are hot, high-energy explosions, so ultraviolet (UV) coverage
is important to better measure the total luminosity and determine its
origin, in particular whether it originates from shocks or simply a
hot photosphere. The Ultraviolet/Optical Telescope (UVOT; Roming et al.
2005SSRv..120...95R 2005SSRv..120...95R) on the Swift satellite (Gehrels et al.
2004ApJ...611.1005G 2004ApJ...611.1005G) presents an excellent opportunity to obtain
unique, early-time UV data. This paper will focus on three objects:
SN 2009dc - a well-studied member of the Super-Chandrasekhar mass SN
class - and SNe 2011aa and 2012dn, which share some characteristics.
Objects:
---------------------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------------------
15 51 12.12 +25 42 28.0 SN 2009dc = SN 2009dc
07 36 42.63 +74 26 34.8 SN 2011aa = PSN J07364263+7426348
20 23 36.26 -28 16 43.4 SN 2012dn = PSN J20233626-2816434
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File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
stars.dat 34 3 List of studied supernovae
table1.dat 48 271 UVOT photometry
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See also:
II/339 : Swift/UVOT Serendipitous Source Catalog (Yershov, 2015)
J/AJ/137/4517 : UVOT light curves of supernovae (Brown+, 2009)
J/ApJ/721/1608 : Absolute UV magnitudes of type Ia SNe (Brown+, 2010)
J/MNRAS/410/585 : SN 2009dc BVRI light curves (Silverman+, 2011)
J/ApJ/749/18 : Swift/UVOT observations of 12 nearby SN-Ia (Brown+, 2012)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- SN Supernova identifier
12- 13 I2 h RAh Simbad Right ascension (J2000)
15- 16 I2 min RAm Simbad Right ascension (J2000)
18- 22 F5.2 s RAs Simbad Right ascension (J2000)
24 A1 --- DE- Simbad Declination sign (J2000)
25- 26 I2 deg DEd Simbad Declination (J2000)
28- 29 I2 arcmin DEm Simbad Declination (J2000)
31- 34 F4.1 arcsec DEs Simbad Declination (J2000)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- SN Supernova identifier (SN YYYYaa in Simbad)
10- 11 A2 --- Filter Swift/UVOT filter used in the observation
13- 22 F10.4 d MJD Modified Julian Date of observation
24- 29 F6.3 mag mag ? Observed magnitude in Filter
31- 35 F5.3 mag e_mag ? Error in mag
37- 42 F6.3 ct/s CR ? Count rate
44- 48 F5.3 ct/s e_CR ? Error in CR
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 23-Jun-2017