Deep optical imaging of the γ-ray pulsar J1048-5832 with the VLT
Abstract
Context. PSR J1048-5832 is a young radio-pulsar that has recently been detected in γ-rays with Fermi, and also in X-rays with Chandra and XMM-Newton. It powers a compact pulsar wind nebula visible in X-rays and is in many ways similar to the Vela pulsar.
Aims: We present deep optical observations made with the ESO Very Large Telescope to search for optical counterparts of the pulsar and its nebula and to explore their multi-wavelength emission properties.
Methods: The data were obtained in the V and R bands and were compared with archival data in other spectral domains.
Results: We do not detect the pulsar in the optical and derive informative upper limits of R ≳ 28.m1 and V ≳ 28.m4 for its brightness. Using a red-clump star method, we estimate an interstellar extinction towards the pulsar of AV ≈ 2 mag, which is consistent with the absorbing column density derived from X-rays. The respective distance agrees with the dispersion measure distance. We reanalysed the Chandra X-ray data and compared the dereddened upper limits with the unabsorbed X-ray spectrum of the pulsar. We find that regarding its optical-X-ray spectral properties this γ-ray pulsar is not distinct from other pulsars detected in both ranges. However, like the Vela pulsar, it is very inefficient in the optical and X-rays. Among a dozen optical sources overlapping with the pulsar X-ray nebula we find one with V ≈ 26.m9 and R ≈ 26.m3, whose colour is slightly bluer than that of the field stars and is consistent with the peculiar colours typical for pulsar nebula features. It positionally coincides with a relatively bright feature of the pulsar X-ray nebula, resembling the Crab wisp and is located in ~2 from the pulsar. We suggest this source as a counterpart candidate to the feature.
Conclusions: Based on the substantial interstellar extinction towards the pulsar and its optical inefficiency, additional optical studies should be carried out at longer wavelengths.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 2013
- DOI:
- 10.1051/0004-6361/201220161
- arXiv:
- arXiv:1302.0755
- Bibcode:
- 2013A&A...552A.127D
- Keywords:
-
- stars: neutron;
- ISM: supernova remnants;
- pulsars: individual: PSR J1048-5832;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 8 pages, 7 figures, 3 tables, accepted for publication in Astronomy and Astrophysics