|Article in PDF||
vol. 9, N 4 (2009)
|#1. Astrotel Observatory, Karachay-Cherkessia, Russia;
#2. Surgut, Russia
Received: 23.01.2009; accepted: 11.02.2009
(E-mail for contact: email@example.com, firstname.lastname@example.org, email@example.com)
1. Four observed primary minima: HJD 2454782.2109, 2454783.3101, 2454783.5892, 2454815.5632. Min II = 17.31. O`Connell effect.
2. Three observed primary minima: HJD 2454703.4495, 2454782.2610, 2454783.2531. Min II = 17.30.
3. We observed four primary minima: HJD 2454723.4702, 2454746.3330, 2454783.2555, 2454815.4833. Min II = 17.53.
4. Min II = 15.70. O`Connell effect.
5. We observed five primary minima: HJD 2454782.5474, 2454783.4642, 2454815.5457, 2454826.5462, 2454827.4634. Min II = 17.49.
6. Min II = 16.46.
7. Two observed primary minima: HJD 2454739.4327, 2454746.3434. Min II = 17.63.
8. Three observed primary minima: HJD 2454782.3985, 2454783.3170, 2454827.4154. Min II = 16.98.
9. Min II = 16.19. Possibly RS-type variability in maximum brightness.
10. Two observed primary minima: HJD 2454782.2460, 2454826.4431. Min II = 15.83:. O'Connell effect.
11. The periods 0.29779 d (type RRC), 0.59563 d and 0.63533 d (both type EW) are also possible. J-K = 0.670 (2MASS).
During observations of the field of the soft gamma repeater SGR0501+4516 (Barthelmy et al. 2008), we discovered 11 new variable stars. Our observations were carried out at the Astrotel-Caucasus observatory using the 300-mm Ritchey-Chretien telescope, equipped with an unfiltered Apogee Alta U9000 CCD camera. In total, 824 images with 5-minute exposures were obtained on JD 2454702 - 2454829. For basic reductions for dark current, flat fields and bias, we used MaxIm DL software. For search and photometry of new variable stars, we applied VaST software by Sokolovsky and Lebedev (2005). The comparison star was USNO-B1.0 1351-0128409 (05:02:03.24, +45:06:16.1, (J2000), R1 = 14.13, R2 = 14.16). Unfiltered magnitudes were calibrated assuming Rcomp = 14.145. The coordinates of the variable stars in the table were drawn from the 2MASS catalogue (Cutri et al. 2003). Our observations were analyzed using Peranso software (www.peranso.com).
Acknowledgements: We would like to thank S.V. Antipin and N.N. Samus for helpful discussions.
Barthelmy, S.D., Baumgartner, W.H., Beardmore, A.P., et al., 2008, The Astronomer's Telegramm, 1676
Cutri, R.M., Skrutskie, M.F., van Dyk, S, et al., 2003, 2MASS All Sky Catalog of Point Sources, Centre de Donnees Astronomiques de Strasbourg, II/246
Sokolovsky, K., Lebedev, A., 2005, in 12th Young Scientists' Conference on Astronomy and Space Physics, Kyiv, Ukraine, April 19-23, 2005, eds.: Simon, A., Golovin, A., p.79