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ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidateстатья
- Авторы: Dornic D., Lipunov V., Basa S., Evans P.A., Kennea J.A., Gorbovskoy E., Tyurina N., Buckley D., Rebolo R.
- Журнал: The Gamma-Ray Coordinates Network Circular
- Том: 18240
- Номер: 1
- Год издания: 2015
- Первая страница: 1
- Аннотация: TITLE: GCN CIRCULAR NUMBER: 18240 SUBJECT: ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate DATE: 15/09/04 19:54:20 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs <lipunov@xray.sai.msu.ru> D. Dornic (CPPM), V.Lipunov (Lomonosov MSU), S. Basa (LAM), P. A. Evans (U. Leicester), J. A. Kennea (PSU), E.Gorbovskoy and N. Tyurina (Lomonosov MSU), D. Buckley (SAAO), R. Rebolo (IAC) MASTER-SAAO robotic telescope (MASTERÂNet: http://observ.pereplet.ru) located in Sutherland received Antares neutrino alert at 2015-09-01 07:38:24.99UT (sunrise) in 16s after trigger time. So and we start observations at nearest available time. MASTER-SAAO automatically started Inspect  survey on the Antares neutrino Alert150901.32 errorÂbox (ra=16 25 42 dec=Â27 23 24 r=1.726600) 35107 sec after notice time and 35123 sec after trigger time (2015-09-01 07:38:24.99, sunrise) at 2015Â09Â01 17:23:48 UT. Observations were up to 2015-09-01 20:25:18 (very cloudy) . MASTER auto-detection system didn’t find any real transient inside the neutrino error box, the unfiltered optical limit on single images is 18.5-19.8 (180s), the sum limit is 20.6 (540s). Observations were continuing on 2015-09-03 17:13:59 (sunset) up to 2015-09-03 21:21:59 (the weather disappeared). We observed in parallel MASTER twin tubes in different filters BV, RI.  The optical limit in B filter on single images was m_B_lim=19.1 (180s), 19.6 on sum (540s) in V filter: m_V_lim=19.3(180s), 19.9 on the sum(540s). The optical limit n R is m_R_lim=18.4-19.0 on single images(60-180s), m_R_lim=19.7-20.3 on sum (540s-1800s). The limit in I was m_I_lim=17.5-18.0 on single images(180s), 18.5 on sum (540s). MASTER-IAC robotic telescope automatically started Inspect observations on 2015-09-01 21:02:44, observed up to 2015-09-01 21:17:34, unfiltered  (W=0.2B+0.8R, USNOB1 calibrated) limit m_lim=18.7-19.2 (180s exposition), 19.8(540s). Observations were continuing in B and V on 2015-09-03 20:08:40 up to 2015-09-03 22:09:12 with limit up to 19.8 in B(180s) and 18.6 in V (180s). No optical transient inside the neutrino error box. The Swift location 16h 26m 02.1s -27d 18m 14s  is difficult for observations from Nothern hemisphere (MASTER-Kislovodsk, -Tunka, -Ural, -Amur). It can be observed at sunset near the horizon. MASTER-Kislovodsk: 02 of Sept there was rain at this observatory at sunset. MASTER-Kislovodsk robotic telescope automatically started Inspect survey on Antares Alert Alert150901.32 on 2015-09-03 16:39:11 UT, at sunset (Object: Altitude: 14.85, Sun: Altitude: -10.65), and were continuing up to 2015-09-03 18:04:47 when the objects’ set. The first hour we have 7  of 30-s expositions  with bad weather condition, the optical limit in V is 12.0-14.1. Unfiltered observations  starts from 2015-09-03 17:21:39 (Object’s Altitude: 11.01)with optical limit 17.8 on single images (60s expositions), 18.4 on sum (180s). No optical transients detected by MASTER auto-detection system inside ANTARES error-box. MASTER-Tunka robotic telescope started observations of this alert at sunset at 2015-09-03 12:40:59. The Object’s Altitude was 6.86 , the Sun: Altitude: -8.12. Very close to horizon, the object goes under it, 16 expositions of 60s in V,R , no OT inside ANTARES error-box.. MASTER-SAAO optical light curve of bright star USNO-B1.0 0626-0501169 inside Swift XRT error box  in B,V,R and I bands (top diagram) and color diagram (bottom) represented here: http://master.sai.msu.ru/static/master_antares_alert_150901.png The source is stable in all four band as well as its color. The average color is: B-V = 0.93 +- 0.06 R-I = 1.07 +- 0.03 A few words about association USNO-B1.0 0626-0501169 and X-ray Swift source (Dornic et al. GCN 18231, ATel #7987 ). Following Swift XRT observation the X-ray flux is changing from 5e-13 to 4e-12 erg/cm2/s (in 0.3-10keV). Full optical flux in MASTER system calibrates as: 15 mag correspond 6.4 10<sub>-12</sub> erg/sm<sub>2</sub>/s . MASTER-SAAO observations of USNO-B1.0 0626-0501169 in January, May and September 2015 show that unfiltered magnitude is m (unfiltered) = 12.36 +-0.03 (Jan); 12.32+- 0.03(May) and 12.32+-0.04 (Sep). Thus it can be argued that the brightness of the star has not changed by more than 3%. Since the X-ray emission occurs near the stellar photosphere, so due to the heating effect of its brightness should slightly increase. The observed brightness of the star persistence restricts the change in X-ray flux in September compared with a May and January: F_x/ F_opt < 3 %. Consequently, F_x < 7 e-11 erg/s. This means that the X-ray heating can not cause optical variability more than 0.003 magnitude. It seems the X-ray is result of the X-ray flare activity of the star (de Ugarte Postigo et al. GCN 18236, ATel #7994; Smartt et al. ATel 7992; Dichiara et al. ATel#7993 ). There is Globular Cluster M4 (NGC621) with millisecond pulsar (Lyne et al., 1988, Nature, V.332, 45-47) and possible massive (~10e3 Solar Mass) black hole inside ANTARES alert 3-sigma error box (the MASTER images of the Antares error box is available at http://master.sai.msu.ru/static/Antares_alert_Image.jpeg By the way there is star Antares (1.3 degrees from center ANTARES error box, but outside! ). So, we propose M4 (with relativistic objects inside) is the possible source of the neutrino, which created after cosmic partical acceleration. The follow up millisecond pulsars observations request. The message may be cited.
- Добавил в систему: Липунов Владимир Михайлович