J/ApJ/794/23 Pan-STARRS1 transients optical photometry (Drout+, 2014)
Rapidly evolving and luminous transients from Pan-STARRS1.
Drout M.R., Chornock R., Soderberg A.M., Sanders N.E., McKinnon R.,
Rest A., Foley R.J., Milisavljevic D., Margutti R., Berger E., Calkins M.,
Fong W., Gezari S., Huber M.E., Kankare E., Kirshner R.P., Leibler C.,
Lunnan R., Mattila S., Marion G.H., Narayan G., Riess A.G., Roth K.C.,
Scolnic D., Smartt S.J., Tonry J.L., Burgett W.S., Chambers K.C.,
Hodapp K.W., Jedicke R., Kaiser N., Magnier E.A., Metcalfe N., Morgan J.S.,
Price P.A., Waters C.
<Astrophys. J., 794, 23 (2014)>
=2014ApJ...794...23D 2014ApJ...794...23D (SIMBAD/NED BibCode)
ADC_Keywords: Supernovae ; Photometry, ugriz ; Surveys ; Redshifts ; Reddening
Keywords: supernovae: general
Abstract:
In the past decade, several rapidly evolving transients have been
discovered whose timescales and luminosities are not easily explained
by traditional supernovae (SNe) models. The sample size of these
objects has remained small due, at least in part, to the challenges of
detecting short timescale transients with traditional survey cadences.
Here we present the results from a search within the Pan-STARRS1
Medium Deep Survey (PS1-MDS) for rapidly evolving and luminous
transients. We identify 10 new transients with a time above
half-maximum (t1/2) of less than 12 days and -16.5>M>-20 mag.
This increases the number of known events in this region of SN phase
space by roughly a factor of three. The median redshift of the PS1-MDS
sample is z=0.275 and they all exploded in star-forming galaxies. In
general, the transients possess faster rise than decline timescale and
blue colors at maximum light (gP1-rP1≲-0.2). Best-fit
blackbodies reveal photospheric temperatures/radii that expand/cool
with time and explosion spectra taken near maximum light are dominated
by a blue continuum, consistent with a hot, optically thick, ejecta.
We find it difficult to reconcile the short timescale, high peak
luminosity (L>1043 erg/s), and lack of UV line blanketing observed
in many of these transients with an explosion powered mainly by the
radioactive decay of 56Ni. Rather, we find that many are consistent
with either (1) cooling envelope emission from the explosion of a star
with a low-mass extended envelope that ejected very little (<0.03 M☉)
radioactive material, or (2) a shock breakout within a dense,
optically thick, wind surrounding the progenitor star. After
calculating the detection efficiency for objects with rapid timescales
in the PS1-MDS we find a volumetric rate of 4800-8000 events/yr/Gpc3
(4%-7% of the core-collapse SN rate at z=0.2).
Description:
PS1 is a wide-field imaging system dedicated to survey observations.
Located on Haleakala, Hawaii, it possesses a 1.8 m diameter primary
mirror and a 3.3° diameter field of view (Kaiser et al.
2010SPIE.7733E..0EK). The imager consists of an array of sixty
4800x4800 pixel detectors with a pixel scale of 0.258'', providing an
instantaneous field of view of 7.1 deg2 (Tonry & Onaka 2009,
Advanced Maui Optical and Space Surveillance Technologies Conference).
Observations are obtained with a set of five broadband filters
(gP1rP1iP1zP1yP1, hereafter grizyP1) which are similar,
although not identical, to those used by the Sloan Digital Sky Survey
(SDSS; Ahn et al. 2012ApJS..203...21A 2012ApJS..203...21A). Details of the filters and
photometry system are given in Tonry et al. (2012, J/ApJ/750/99) and
Stubbs et al. (2010ApJS..191..376S 2010ApJS..191..376S).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 96 14 Basic Observational Information
table2.dat 48 535 Optical Photometry
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See also:
J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 2012)
J/ApJ/799/208 : Type IIP supernovae from Pan-STARRS1 (Sanders+, 2015)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 A1 --- Sample [ABC] Transient sample name (1)
3- 6 A4 --- --- [PS1-]
7- 11 A5 --- PS1 Transient name (PS1 -YYaaa in Simbad)
13- 23 A11 "date" Date Date of the observation
25- 26 I2 h RAh Hour of Right Ascension (J2000)
28- 29 I2 min RAm Minute of Right Ascension (J2000)
31- 36 F6.3 s RAs Second of Right Ascension (J2000)
38 A1 --- DE- Sign of the Declination (J2000)
39- 40 I2 deg DEd Degree of Declination (J2000)
42- 43 I2 arcmin DEm Arcminute of Declination (J2000)
45- 49 F5.2 arcsec DEs Arcsecond of Declination (J2000)
51- 55 F5.3 --- z ? Redshift
57- 62 F6.1 Mpc Dist ? Luminosity distance
64- 69 F6.1 0.1nm lambdag ? gP1 effective pivot wavelength (in Å)
71- 76 F6.1 0.1nm lambdar ? rP1 effective pivot wavelength (in Å)
78- 83 F6.1 0.1nm lambdai ? iP1 effective pivot wavelength (in Å)
85- 90 F6.1 0.1nm lambdaz ? zP1 effective pivot wavelength (in Å)
92- 96 F5.3 mag E(B-V) Milky Way reddening in the direction of each
transient
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Note (1): Name as follows:
A = Gold Sample;
B = Silver Sample;
C = Bronze Sample.
Transients can be usefully split into three groups based on the quality of
their observed light curves and constraints available on their distances.
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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- 4 A4 --- --- [PS1-]
5- 9 A5 --- PS1 Transient name (PS1 -YYaaa in Simbad)
11- 14 A4 --- Filter Filter used in the observation
16- 22 F7.1 d MJD Observation Modified Julian Dated
24- 28 F5.1 d Phase ?=-99.9 Rest Frame Days Since Observed
gP1 maximum (1)
30 A1 --- l_mag [<] 3σ upper limit flag on mag
31- 35 F5.2 mag mag Observed magnitude in Filter
39- 42 F4.2 mag e_mag ? Uncertainty in mag (2)
44- 48 A5 --- Inst Instrument on which observations were taken
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Note (1): Value -99.9 signifies that no redshift was obtained for this object.
Note (2): No value signified that the quoted mag is a 3σ upper limit.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 24-Apr-2017