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Optical spectroscopy and photometry of the neutron star RX J1856.5-3754

van Kerkwijk, M. H. and Kulkarni, S. R. (2001) Optical spectroscopy and photometry of the neutron star RX J1856.5-3754. Astronomy & Astrophysics, 378 (3). pp. 986-995. ISSN 0004-6361. doi:10.1051/0004-6361:20011272.

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We present spectroscopy and imaging with the Very Large Telescope (VLT) of the neutron star RX J1856.5-3754. Little is known about the nature of this source other than that it is a nearby hot neutron star. Our VLT spectrum does not show any strong emission or absorption features. With considerable care to photometric calibration, we obtain photometric measurements over the optical and ultra-violet (UV) using our VLT observations and a detailed analysis of archival Hubble Space Telescope data. We find that the entire optical to UV spectral energy distribution is well described by a slightly reddened Rayleigh-Jeans tail (f_λ = (2.96 ± 0.06) x 10^(-19) (λ/5000˚A)^(−4) 10^((−0.4)(0.12±0.05)(A_λ/A_V −1.138)) erg s^(−1) cm^(−2) ˚A^(−1), where A_λ/A_V, where is the reddening curve; implied V = 25.58 ± 0.02). The reddening is consistent with the interstellar absorption inferred from X-ray spectroscopy. The simplest explanation for this Rayleigh-Jeans emission is that the optical-UV radiation arises from thermal emission from the surface of the neutron star. The high degree to which the data conform to the Rayleigh-Jeans tail significantly limits contributions from other sources of emission. In particular, our observations are inconsistent with the presence of an accretion disk and also strongly constrain the amount of magnetospheric emission from this enigmatic neutron star.

Item Type:Article
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URLURL TypeDescription Paper
Kulkarni, S. R.0000-0001-5390-8563
Additional Information:© ESO, 2001. Received 18 June 2001 / Accepted 6 September 2001 We thank the ESO staff, in particular Thomas Szeifert and Hermann Böhnhardt, for their expert help with both observing runs. This research made use of the SIMBAD data base. The Munich Image Data Analysis System is developed and maintained by the European Southern Observatory. M.H.vK. acknowledges support of a fellowship from the Royal Netherlands Academy of Science, and S.R.K. support from NASA and NSF.
Funding AgencyGrant Number
Royal Netherlands Academy of ScienceUNSPECIFIED
Subject Keywords:stars: individual: RX J1856.5-3754 / stars: neutron / X-rays: stars
Issue or Number:3
Record Number:CaltechAUTHORS:20170408-172243891
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Official Citation:Optical spectroscopy and photometry of the neutron star RX J1856.5-3754 M. H. van Kerkwijk and S. R. Kulkarni A&A, 378 3 (2001) 986-995 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76335
Deposited By: 1Science Import
Deposited On:13 Mar 2018 20:48
Last Modified:15 Nov 2021 16:59

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