Optical counterpart to IGR J16465-4507
ATel #429; Ignacio Negueruela (Alicante), David M. Smith (U. C. Santa Cruz), Sylvain Chaty (CEA-Saclay)
on 28 Feb 2005; 17:56 UT
Credential Certification: Ignacio Negueruela (firstname.lastname@example.org)
Subjects: Optical, Binary, Neutron Star, Transient
Referred to by ATel #: 470
Intermediate resolution spectra of the only star in the XMM-Newton error box for IGR J16465-4507 (ATel #329, #336), USNO-B1.0 0448-00520455 = 2MASS J16463526-4507045, have been taken with the 3.5-m NTT, in La Silla (ESO proposal 274.D-0510). As anticipated in ATel #338, the star is a reddened
early-type supergiant and hence certainly the correct counterpart.
The spectral type is estimated at B0.5I. The H-alpha line shows a broad emission component on top of the photospheric profile.
It seems clear now that XTE J1739-302, IGR J17544-2619 and IGR J16465-4507 define a new class of high mass X-ray transients, characterised by very short outbursts and evolved counterparts (cf. Atel #338).