Infrared Candidates for the Intense Galactic X-ray Source GX 17+2

Details Infrared Candidates for the Intense Galactic X-ray Source GX 17+2 Infrared Candidates for the Intense Galactic X-ray Source GX 17+2

1999-05-14

arxiv.org/abs/astro-ph/9905174v1

Astrophys.J. 524 (1999) 406

Astronomy and Astrophysics

Astrophysics

15 pages including 3 figures and 3 tables. Accepted for publication in The Astrophysical Journal

Scientific paper

10.1086/307803

We present new astrometric solutions and infrared Hubble Space Telescope observations of GX 17+2 (X1813-140), one of the brightest X-ray sources on the celestial sphere. Despite 30 years of intensive study, and the existence of a strong radio counterpart with a sub-arcsecond position, the object remains optically unidentified. The observed X-ray characteristics strongly suggest that it is a so-called "Z-source," the rare but important category that includes Sco X-1 and Cyg X-2. Use of the USNO-A2.0 catalog enables us to measure the position of optical and infrared objects near the radio source to sub-arcsecond precision within the International Celestial Reference Frame, for direct comparison with the radio position, which we also recompute using modern calibrators. With high confidence we eliminate the V~17.5 star NP Ser, often listed as the probable optical counterpart of the X-ray source, as a candidate. Our HST NICMOS observations show two faint objects within our 0.5" radius 90% confidence error circle. Even the brighter of the two, Star A, is far fainter than expected (H~19.8), given multiple estimates of the extinction in this field and our previous understanding of Z sources, but it becomes the best candidate for the counterpart of GX 17+2. The probability of a chance coincidence of an unrelated faint object on the radio position is high. However, if the true counterpart is not Star A, it is fainter still, and our conclusion that the optical counterpart is surprisingly underluminous is but strengthened.

Affiliated with

Also associated with

No associations

Rating

Infrared Candidates for the Intense Galactic X-ray Source GX 17+2 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Infrared Candidates for the Intense Galactic X-ray Source GX 17+2, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Infrared Candidates for the Intense Galactic X-ray Source GX 17+2 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-722089