SN 2002bu-ANOTHER SN 2008S-LIKE TRANSIENT
- Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States)
- Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)
We observed supernova (SN) 2002bu in the near-IR with the Hubble Space Telescope (HST), the mid-IR with the Spitzer Space Telescope, and in X-rays with Swift 10 years after the explosion. If the faint L {sub H} {approx} 10{sup 2} L {sub Sun} HST near-IR source at the transient position is the near-IR counterpart of SN 2002bu, then the source has dramatically faded between 2004 and 2012, from L {approx_equal} 10{sup 6.0} L {sub Sun} to L {approx_equal} 10{sup 4.5} L {sub Sun }. It is still heavily obscured, {tau} {sub V} {approx_equal} 5 in graphitic dust models, with almost all the energy radiated in the mid-IR. The radius of the dust emission is increasing as R{proportional_to}t {sup 0.7{+-}0.4} and the optical depth is dropping as {tau} {sub V}{proportional_to}t {sup -1.3{+-}0.4}. The evolution expected for an expanding shell of material, {tau} {sub V}{proportional_to}t {sup -2}, is ruled out at approximately 2{sigma}, while the {tau} {sub V}{proportional_to}t {sup -0.8} to t {sup -1} optical depth scaling for a shock passing through a pre-existing wind is consistent with the data. If the near-IR source is a chance superposition, the present-day source can be moderately more luminous, significantly more obscured and evolving more slowly. While we failed to detect X-ray emission, the X-ray flux limits are consistent with the present-day emissions being powered by an expanding shock wave. SN 2002bu is clearly a member of the SN 2008S class of transients, but continued monitoring of the evolution of the spectral energy distribution is needed to conclusively determine the nature of the transient.
- OSTI ID:
- 22086349
- Journal Information:
- Astrophysical Journal, Vol. 760, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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