J/other/Nat/463.513 Radio observations of SN 2009bb (Soderberg+, 2010)
A relativistic type Ibc supernova without a detected gamma-ray burst.
Soderberg A.M., Chakraborti S., Pignata G., Chevalier R.A., Chandra P.,
Ray A., Wieringa M.H., Copete A., Chaplin V., Connaughton V.,
Barthelmy S.D., Bietenholz M.F., Chugai N., Stritzinger M.D., Hamuy M.,
Fransson C., Fox O., Levesque E.M., Grindlay J.E., Challis P., Foley R.J.,
Kirshner R.P., Milne P.A., Torres M.A.P.
<Nature, 463, 513-515 (2010)>
=2010Natur.463..513S 2010Natur.463..513S
ADC_Keywords: Supernovae ; Radio continuum
Abstract:
Long duration gamma-ray bursts (GRBs) mark the explosive death of some
massive stars and are a rare sub-class of type Ibc supernovae. They
are distinguished by the production of an energetic and collimated
relativistic outflow powered by a central engine (an accreting black
hole or neutron star). Observationally, this outflow is manifested in
the pulse of gamma-rays and a long-lived radio afterglow. Until now,
central-engine-driven supernovae have been discovered exclusively
through their gamma-ray emission, yet it is expected that a larger
population goes undetected because of limited satellite sensitivity or
beaming of the collimated emission away from our line of sight. In
this framework, the recovery of undetected GRBs may be possible
through radio searches for type Ibc supernovae with relativistic
outflows. Here we report the discovery of luminous radio emission from
the seemingly ordinary type Ibc SN 2009bb, which requires a
substantial relativistic outflow powered by a central engine. A
comparison with our radio survey of type Ibc supernovae reveals that
the fraction harbouring central engines is low, about one per cent,
measured independently from, but consistent with, the inferred rate of
nearby GRBs. Independently, a second mildly relativistic supernova has
been reported.
Objects:
-------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------
10 31 33.9 -39 57 30 SN 2009bb = SN 2009bb
-------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 63 16 Very Large Array observations of SN 2009bb
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Date UT date (MM/DD.d, 2009)
10- 15 F6.3 mJy F1.43 ?=- Flux density at 1.43GHz
17- 21 F5.3 mJy e_F1.43 ?=- rms uncertainty on F1.43
23- 28 F6.3 mJy F4.86 ?=- Flux density at 4.86GHz
30- 34 F5.3 mJy e_F4.86 ?=- rms uncertainty on F4.86GHz
36- 41 F6.3 mJy F8.46 Flux density at 8.46GHz
43- 47 F5.3 mJy e_F8.46 rms uncertainty on F8.46GHz
49- 53 F5.3 mJy F22.5 ?=- Flux density at 22.5GHz
55- 59 F5.3 mJy e_F22.5 ?=- rms uncertainty on F22.5GHz
61- 63 A3 --- VLA VLA configuration
--------------------------------------------------------------------------------
Table 2 : GMRT observations of SN 2009bb.
-----------------------------------------------------------------
Date Frequency Flux Density Synthesized Beam Size
(UT) (MHz) (mJy) (arcsec)
-----------------------------------------------------------------
May 31.5 1287 4.6±0.3 5x2
Jun 10.6 617 3.0±0.3 10x4
Aug 8.3 617 7.9±0.3 10x4
Aug 10.4 332 3.3±0.7 13x7
-----------------------------------------------------------------
Table 3. X-ray observations of SN 2009bb.
------------------------------------------------------------------
Date Exposure Flux Mission
(UT) (sec) (mW/m2)
------------------------------------------------------------------
Mar 24.1 3964 ≲1.3x10-13 Swift/XRT
Apr 6.2 9829 ≲1.7x10-13 Swift/XRT
Apr 10.5 6720 ≲2.5x10-13 Swift/XRT
Apr 18.7 12752 ≲3.0x10-13 Swift/XRT
Apr 18.6 9914 2.3±0.5x10-14 Chandra
------------------------------------------------------------------
Notes: All measurements are 0.3-10keV and unabsorbed.
Upper limits are dominated by diffuse host galaxy emission.
------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 12-Feb-2010