Optical Classification of Three Swift BAT/XRT Sources at Low Galactic Latitude

ATel #847; J. P. Halpern (Columbia U.)
on 28 Jun 2006; 20:02 UT
Credential Certification: Jules Halpern (jules@astro.columbia.edu)

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I report optical spectroscopic classifications of three Swift BAT/XRT sources at low Galactic latitude from the lists of Tueller et al. (ATel #669) and Kennea et al. (ATel #677). Each of the counterparts, whose positions are within their respective Swift XRT error circles, are present in the USNO-B1.0 and 2MASS catalogs, from which data are reproduced below. Spectra were obtained on 2006 June 24-25 UT using the Hiltner 2.4m telescope of the MDM Observatory and the Modular Spectrograph. The wavelength range 421-759 nm was covered at 0.5 nm resolution. These bright objects were used as "backup" targets when observing conditions were mediocre to poor.

Swift J1930.5+3414 (ATel #677): Seyfert 1 galaxy at z=0.0629, based on H-alpha, [O III]5007,4959, and H-beta emission. The H-alpha line is broad and skewed. Also detected in the NVSS (3.9±0.5 mJy at 1.4 GHz).
RA = 19h 30m 13.80s, Decl. = +34° 10' 49.4" (J2000).
B2=16.08, R2=15.79, I2=15.09, J=14.24, H=13.07, K=11.81.

Swift J2000.6+3210 (ATel #669): H-alpha emission of EW -1.0 nm at zero redshift. No other emission lines. Prominent diffuse interstellar bands and Na I D absorption. At the low Galactic latitude of +1.1°, these properties are consistent with a Be/X-ray binary.
RA = 20h 00m 21.86s, Decl. = +32° 11' 23.4" (J2000).
B2=17.13, R2=15.50, I2=14.40, J=11.95, H=11.29, K=10.85.

Swift J2127.4+5654 (ATel #669): Narrow-line Seyfert 1 Galaxy at z=0.0147, with H-alpha, He I 5876, [O III]5007,4959, H-beta emission. The NLS1 classification is based on FWHM(H-alpha) ~ 1180 km/s. This source was also detected in the ROSAT All-Sky Survey, where it was characterized as variable (Fuhrmeister & Schmitt, 2003, A&A, 403, 247), the ROSAT HRI, and the NVSS (6.4±0.5 mJy at 1.4 GHz). At Galactic latitude +4.4°, extinction in this direction is high, E(B-V) = 1.30 according to Schlegel et al. 1998, ApJ, 500, 525.
RA = 21h 27m 45.33s, Decl. = +56° 56' 35.0" (J2000).
B2=18.79, R2=14.81, I2=13.29, J=13.27, H=11.84, K=10.59.