Difference: GCNCIRCULAR21687 ( vs. 1)

V.M.Lipunov, E. Gorbovskoy, V.G.Kornilov, N.Tyurina, V.Shumkov, D.Kuvshinov, P.Balanutsa, O.Gress, A.Kuznetsov, M.I.Panchenko, A.V.Krylov, I.Gorbunov Lomonosov Moscow State University, Sternberg Astronomical Institute

R.Podesta, C.Lopez, F.Podesta Observatorio Astronomico Felix Aguilar (OAFA) , National University of San Juan, Argentina

H.Levato, C.Saffe Instituto de Ciencias Astronomicas,de la Tierra y del Espacio (ICATE), San Juan, Argentina

D.Buckley, S.Potter, M.Kotze, South African Astronomical Observatory

N.M. Budnev, O. Gress, K. Ivanov, S.Yazev Irkutsk State University

V.Yurkov, Yu.Sergienko, A.Gabovich Blagoveschensk Educational State University, Blagoveschensk

R. Rebolo, M. Serra-Ricart, G. Israelian, N.Lodiu The Instituto de Astrofisica de Canarias

A. Tlatov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory

MASTER Global Robotic Net (http:/ / observ.pereplet.ru/ ) consists of a new generation of fast robotic telescopes that installed on different continents during recent years.

MASTER-II are twin 40 cm wide field (2x4 square degrees, 1 pixel = 2.0 arcsec) optical robotic telescopes located in the following observatories: MASTER-Amur (far east of Russia, Blagoveshchensk), MASTER-Tunka (Russia, Baykal lake), MASTER-Kislovodsk, MASTER-Tavrida (Russia), MASTER-SAAO (South Africa), MASTER-IAC (Spain, Canarias), and MASTER-OAFA (Argentina, MASTER I yet).

MASTER observatories are equipped with their own identical photometers and are controlled by identical software (Lipunov et al., "MASTER Global Robotic Net", Advances in Astronomy, 2010, 30L).

The identical equipment gives us the possibility of having up to 24 continuous hours observations of optical counterparts of GRBs in identical photometric systems. Therefore, combining photometric data for different GRBs observed from different parts of the MASTER Net is a well-justified astronomical process (see last result in Troya, Lipunov, Mundel et al., Nature, 2017, vol.547,425-427)

Taking into account the large field of view of the MASTER II telescopes (8 square degrees), we can use a large number (1000 - 5,000) of reference stars for reduction. As a result, the photometric errors of large catalogs, Tycho II and USNO-B1, shouldbe leveled out.

Global MASTER-Net started to observe LIGO/Virgo G298048 error field at 2017-08-17 17:06:47 UT.

MASTER-SAAO (MASTER II robotic telescope at South Africa Astronomical Observatory, Sutherland) automaticaly have imaged the initial BAYESTAR error field received by socket connection (LVC GCN 21505) including common region with Fermi GBM error box (Connaughton et al., LVC GCN 21506) immediatelly after sunset at 2017-08-17 17:06:47 = 2017-08-17.71304 (JD = 2457983.21304398) i.e. 15943 sec after LVC trigger time (12:41:04 UT) . The coaadded (3x180sec) first unfiltered images limit is 19.8. This image included ICECube candidate N4 (Bartos et al LVC GCN 21511). No OTs found in this error box.

After that MASTER-SAAO telescope continue to image Fermi and LVC initial common error field and all Ice Cube candidates. The unfiltered limits and fields one can find at GraceDB. Cover map is available at

No OTs found at this observations. The Possible KiloNova SSS17a in NGC 4993 (Coulter et al., LVC GCN 21529) is not covering by MASTER-SAAO at 17 Aug 2017.

MASTER-OAFA (MASTER I robotic telescope with FOV = 6 square degrees; at Argentina, Observatorio Astronomico Felix Aguilar (OAFA), National University of San Juan,) have imaged the new BAYESTAR-HLV localization map of LIGO/Virgo G298048 (GCN 21513) starting 2017-08-17 22:54:18 = 2017-08-17.954375 from first field (6 square degrees):

RA, DEC = 12h 59m 00.00s -19d 59m 38.00s

Unforunatelly the first telescope image not include sss17a.

But fortunally there are two MASTER Very Wide Field cameras (FOV = 2x380 square degrees, 22 arcsec in pixel, see Lipunov et al., 2010, MASTER Robotic Net, Advances in Astronomy, vol. 2010, pp. 1-7) at same mount. As the results we have large seria ("video") MASTER VWF cameras images exposition and without time gap of the all LIGO/Virgo G298048 error box include the NGC 4993 galaxy. We see NGC 4993 galaxy on coadded images. After the images substraction with refernce very wide field camera images we see some excess (see Table 1) at NGC 4993 position with flux corresponded to ~15.3 mag.

Starting from 2017-08-17 22:58:48 UT = 2017-08-17 22:58:48 MASTER-OAFA have imaged new BAYESTAR-HLV localization map of LIGO/Virgo G298048 (GCN 21513) with unfiltered images (150 sec exposition) limit 19-20 magnitudes. The coadded images limit grows to 20.5.

At 2017-08-17 23:59:54 UT i.e. 11 h 18m 50 sec after LVC trigger time MASTER-OAFA robotic telescope independently from any optical information take second image with NGC 4993 galaxy where Possible KiloNova SSS17a was published late Coulter et al., LVC GCN 21529, Allam et al. (LVC GCN 21530), Yang et al. (LVC GCN 21531), Melandri et al. (LVC GCN 21532), Lipunov et al., (LVC GCN 21546), Chen et al. (LVC GCN 21608).

On the next 3 days both southern MASTER robotic telescopes at SAAO and OAFA was done (and continue now) B,R, Unfiltered monitoring Possible KiloNova SSS17a at NGC 4993 galaxy.

The covering video map at first day is available at

The photometry of sss17a listed at Table I. This photometry made by substracted images and free from galaxy background.

TableI. MASTER Global Robotic Net the sss17a photometry

2017-08-17 22:54:18 36.794 225x5 V 15.3* 0.5 15.5 MASTER VWFC OAFA
2017-08-17 23:59:54 40.730 180 W 17.7 0.2 19.5 MASTER I OAFA
2017-08-18 00:19:05 41.881 180 W 17.3 0.2 19.3 MASTER I OAFA

2017-08-18 17:06:55 102.352 6x180 W 17.5 0.2 20.0 MASTER II SAAO
2017-08-18 17:17:33 102.989 3x180 R 17.2 0.2 19.8 MASTER II SAAO
2017-08-18 17:34:02 103.979 3x180 B 18.5 0.1 19.5 MASTER II SAAO

2017-08-19 17:06:57 188.753 3x180 W 18.6 0.2 20.0 MASTER II SAAO
2017-08-19 17:53:34 191.550 3x180 R 18.2 0.3 19.8 MASTER II SAAO
2017-08-19 18:04:32 192.208 3x180 B ---- --- 19.5 MASTER II SAAO
2017-08-19 23:13:20 210.736 10x180 W 19.0 0.2 20.7 MASTER I OAFA

2017-08-20 17:04:36 275.012 3x180 W >19.3 --- 20.0 MASTER II SAAO
2017-08-20 17:25:56 276.292 3x180 R >18.8 --- 19.5 MASTER II SAAO
2017-08-20 17:36:32 276.928 3x180 B >19.7 --- 20.0 MASTER II SAAO
2017-08-21 00:26:31 301.527 10x180 W >20.0 --- 20.7 MASTER I OAFA

2017-08-21 17:08:14 361.630 3x180 W >19.3 --- 20.0 MASTER II SAAO
2017-08-21 18:06:12 365.108 3x180 R >18.8 --- 19.5 MASTER II SAAO
2017-08-21 19:20:23 369.559 3x180 B >18.7 --- 19.0 MASTER II SAAO

Ttrig - LVC trigger Time T - is the exposition start time W - unfiltered VWFC - Very Wide Field Camera

Table 2. Start and midle times.

2017-08-17 22:54:18 2457983.454 23:03:40
2017-08-17 23:59:54 2457983.4999 00:01:24
2017-08-18 00:19:05 2457983.513 00:20:35

2017-08-18 17:06:55 2457984.217 17:11:57
2017-08-18 17:17:33 2457984.226 17:25:27
2017-08-18 17:43:02 2457984.236 17:39:14

2017-08-19 17:06:57 2457985.213 17:11:52
2017-08-19 17:53:34 2457985.246 17:58:29
2017-08-19 18:04:32 2457985.253 18:09:27
2017-08-19 23:13:20 2457985.468 23:30:50

2017-08-20 17:04:36 2457986.212 17:09:31
2017-08-20 17:25:56 2457986.226 17:30:51
2017-08-20 17:36:32 2457986.234 17:41:27
2017-08-21 00:26:31 2457986.518 00:44:01

2017-08-21 17:08:14 2457987.214 17:13:09
2017-08-21 18:06:12 2457987.254 18:11:07
2017-08-21 19:20:23 2457987.306 19:25:18

There are MASTER-NET 126 arhival images of the NGC 4993 galaxy since 2015-01-17 00:45:46 till 2017-05-02 22:17:04 . No optical sss17a activity was found. The MASTER arhival images table is available at http://master.sai.msu.ru/static/MASTER_G298048_PREDISCOVERY1.txt .

As the discussion about physical nature GW 170817/G298048 (Lipunov, LVC GCN 21621; Nichol etal., LVC GCN 21585, LVC GCN 21592; D'Elia et al.,LVC GCN 21592 ) I (Vladimir Lipunov) would like to point that distance of the binary NS merging ~ 40 Mpc is in good agreement with predicted merging rate inside local super cluster (Lipunov, Postnov & Prokhorov, 1987, A&A, vol.176, L1-L4.). See fig. 1 which is vailable at .

There was predicted 1 merging NS+NS per year for 20 Mpc radius volume(e-case, see capture). This means, that for 40 Mpc predicted ~ 10 per year!

This message can be citted.

-- ThomasKupfer - 25 Aug 2017