Confirmation of counterpart to SWIFT J1626.6-5156
ATel #739; Ignacio Negueruela, Amparo Marco (University of Alicante)
on 16 Feb 2006; 21:02 UT
Credential Certification: Ignacio Negueruela (ignacio@dfists.ua.es)
Subjects: Optical, Binary, Transient, Pulsar
Referred to by ATel #: 3300
The candidate counterpart to SWIFT J1626.6-5156 (ATel #678, #679, #688) proposed by Rea et al. (ATel #713) was observed on the night of 2006 Feb 15 with the NTT (La Silla, Chile). The instrument used was EMMI with grism #6. This configuration covers the 570-870 nm range with a dispersion of 0.7A/pixel.
The candidate (2MASS16263652-5156305 = USNO-B1.0 0380-0649488) displays H-alpha strongly in emission, with an EW=-38Ã
and broad wings. The Paschen series is also in emission, with Pa 18 rather stronger than other lines, most likely because of an important contribution from OI 8446Ã
. No HeI lines are seen, though HeI 7065Ã
may be very weakly in emission. Weak emission from the OI 7774Ã
triplet is also possibly detected. Though a blue spectrum will be necessary for an exact classification, all these features strongly suggest that the object is a Be star and hence SWIFT J1626.6-5156 is an unusual Be/X-ray binary.
