Chandra, MDM, Swift, and NuSTAR observations confirming the SFXT nature of AX J1949.8+2534
Abstract
AX J1949.8+2534 is a candidate supergiant fast X-ray transient (SFXT) observed in outburst by INTEGRAL (IGR J19498+2534). We report on the results of six Neil Gehrels Swift-XRT, one Chandra, and one NuSTAR observation of the source. We find evidence of rapid X-ray variability on a few ks timescales. Fortunately, Chandra observed the source in a relatively bright state, allowing us to confidently identify the optical/NIR counterpart of the source. We also obtained an optical spectrum of this counterpart, which shows an Hα emission line and He I absorption features. The photometry and spectrum of the source allow us to constrain its distance, 7-8 kpc, and reddening, AV=8.5-9.5. We find that the star is likely an early B-type Ia supergiant, confirming that AX J1949.8+2534 is indeed an SFXT.
Turn this paper into a lesson
ArcXiv compiles a structured reading guide from this paper's metadata: plain-English importance, contributions, prerequisite concepts, which sections to read first, flashcards, and a quiz. Grounded in the abstract, never invented.