Infrared observations of the candidate double neutron star system PSR J1811-1736
arXiv:1212.4801 · doi:10.1093/mnras/sts671
Abstract
PSR J1811-1736 (P=104 ms) is an old (~1.89 Gyrs) binary pulsar (P_orb=18.8 d) in a highly eccentric orbit (e=0.828) with an unidentified companion. Interestingly enough, the pulsar timing solution yields an estimated companion mass 0.93 M_{\odot}<M_C<1.5 M_{\odot}, compatible with that of a neutron star. As such, it is possible that PSR J1811-1736 is a double neutron star (DNS) system, one of the very few discovered so far. This scenario can be investigated through deep optical/infrared (IR) observations. We used J, H, K-band images, obtained as part of the UK Infrared Telescope (UKIRT) Infrared Deep Sky Survey (UKIDSS), and available in the recent Data Release 9 Plus, to search for its undetected companion of the PSR J1811-1736 binary pulsar. We detected a possible companion star to PSR J1811-1736 within the 3 sigma radio position uncertainty (1.32 arcsec), with magnitudes J=18.61+/-0.07, H=16.65+/-0.03, and K=15.46+/-0.02. The star colours are consistent with either a main sequence (MS) star close to the turn-off or a lower red giant branch (RGB) star, at a pulsar distance of ~5.5 kpc and with a reddening of E(B-V)~4.9. The star mass and radius would be compatible with the constraints on the masses and orbital inclination of the binary system inferred from the mass function and the lack of radio eclipses near superior conjunction. Thus, it is possible that it is the companion to PSR J1811-1736. However, based on the star density in the field, we estimated a quite large chance coincidence probability of ~0.27 between the pulsar and the star, which makes the association unlikely. No other star is detected within the 3 sigma pulsar radio position down to J~20.5, H~19.4$ and K~18.6, which would allow us to rule out a MS companion star earlier than a mid-to-late M spectral type.
10 pages, 6 figures, accepted for publication on Monthly Notices of the Royal Astronomical Society
References in corpus (14)
- The UKIRT Infrared Deep Sky Survey (UKIDSS)
- The ATNF Pulsar Catalogue
- The UKIDSS Galactic Plane Survey
- Timing Measurements of the Relativistic Binary Pulsar PSR B1913+16
- The WFCAM Science Archive
- The UKIRT Wide Field Camera ZYJHK Photometric System: Calibration from 2MASS
- The ACS Nearby Galaxy Survey Treasury IX. Constraining asymptotic giant branch evolution with old metal-poor galaxies
- Multi-telescope timing of PSR J1518+4904
- The binary pulsar PSR J1811-1736: evidence of a low amplitude supernova kick
- Detection of X-ray Emission from the Very Old Pulsar J0108-1431
- PSR J1903+0327 : A Unique Milli-Second Pulsar with a Main-Sequence Companion Star
- Complex small-scale structure in the infrared extinction towards the Galactic Centre
- X-ray and optical observations of the closest isolated radio pulsar
- Orbital variation of the X-ray emission from the double neutron star binary J1537+1155