Zooming in on Supernova 1987A at submillimetre wavelengths^⋆

¹ European Organization for Astronomical Research in the Southern Hemisphere (ESO), Karl-Schwarzschild-Str. 2, 85748 Garching b. München Germany
e-mail: mlakicev@eso.org
² Astrophysics Group, Lennard-Jones Laboratories, Keele University, Staffordshire ST5 5BG, UK

Received: 16 December 2011
Accepted: 18 March 2012

Abstract

Context. Supernova 1987A (SN 1987A) in the neighbouring Large Magellanic Cloud offers a superb opportunity to follow the evolution of a supernova and its remnant in unprecedented detail. Recently, far-infrared (far-IR) and sub-mm emission was detected from the direction of SN 1987A, which was interpreted as due to the emission from dust, possibly freshly synthesized in the SN ejecta.

Aims. To better constrain the location and hence origin of the far-IR and sub-mm emission in SN 1987A, we have attempted to resolve the object in that part of the electro-magnetic spectrum.

Methods. We observed SN 1987A during July–September 2011 with the Atacama Pathfinder EXperiment (APEX), at a wavelength of 350 μm with the Submillimetre APEX BOlometer CAmera (SABOCA) and at 870 μm with the Large APEX BOlometer CAmera (LABOCA). The 350-μm image has superior angular resolution (8′′) over that of the Herschel Space Observatory 350-μm image (25′′). The 870-μm observation (at 20′′ resolution) is a repetition of a similar observation made in 2007.

Results. In both images, at 350 and 870 μm, emission is detected from SN 1987A, and the source is unresolved. The flux densities in the new (2011) measurements are consistent with those measured before with Herschel at 350 μm (in 2010) and with APEX at 870 μm (in 2007). A higher dust temperature (≈33 K) and lower dust mass might be possible than what was previously thought.

Conclusions. The new measurements, at the highest angular resolution achieved so far at far-IR and sub-mm wavelengths, strengthen the constraints on the location of the emission, which is thought to be close to the site of SN 1987A and its circumstellar ring structures. These measurements set the stage for upcoming observations at even higher angular resolution with the Atacama Large Millimeter Array (ALMA).