June 22 - GRB 210619B
Observation of the optical afterglow of gamma-ray burst GRB 210619B from ARO. Long-duration GRB 210619B was detected by the Swift Burst Alert Telescope at 23:59:25 UT on June 19, 2021. The peak count rate was ~100,000 counts/sec (15-350 keV); for comparison: the peak count rate of the recent GRB 210610B was ~11,000 counts/sec (15-350 keV). Redshift of 1.937 was reported in the GCN circular #30272 https://gcn.gsfc.nasa.gov/gcn3/30272.gcn3 with information: "GRB 210619B will likely be among the most energetic GRBs" and "the initial prompt emission spike is extremely luminous, and we expect the afterglow to be among the most luminous prompt flashes ever detected".
On June 20, the weather was cloudy for shooting at ARO, but after a day, on June 21 (on the summer solstice, on the shortest night of the year), the sky was clear. Eight images were obtained with a total exposure of 100 minutes with the Rc filter; an optical afterglow with a magnitude of about 20 is clearly visible on the stacked image.
(contributed by ARO/BGO observer Filipp Romanov)
June 12 - GRB 210610B
Observations of optical afterglow of gamma-ray burst GRB 210610B were made on the BGO and ARO telescopes on June 11, 2021.
This long GRB was detected by the Swift Burst Alert Telescope on 19:51:27 UT on June 10, 2021 (redshift value z=1.1345 has been published later). At 02:01:17, shooting of ARO began, and at 02:05:45 imaging at the BGO began. As a result, 6 photographs were obtained with different filters, which clearly showed an optical afterglow with a magnitude of about 17.5 magnitudes. Photometric measurements were published in circular #30228 of the Gamma-ray Coordinates Network:
Below is a stacked image with a total exposure of 67 minutes.
(contributed by ARO/BGO observer Filipp Romanov)
June 2
A new
Observatory Statistics page has been added that provides tables and charts of various statistics by month, year, or all time, extracted from the observatory's databases.
May 5
ARO Observer, Filipp Romanov, reports the following observations which aided in the discovery of a new near-earth minor planet!
Good news: the first Minor Planet Electronic Circular about the discovery of a Near-Earth Object with observations from ARO was published.
On May 2, 2021, I made astrometric measurements from ARO photographs of an asteroid A10WSDY (posted on the NEO Confirmation Page). Despite the slight defocusing and haze in the sky during shooting, I selected two images with better visibility of the object, and sent the measurements to the MPC. As a result, this was published
minorplanetcenter.net/mpec/K21/K21J16.html in the MPEC 2021-J16 with the assignment of the asteroid designation 2021 HC3.
The asteroid has a size of 95-300 meters and on May 4, 2021, on 18:05 UT, it will approach the Earth at 18.5 lunar distances. At perihelion, the asteroid is closer to the Sun than the orbit of Mercury; at aphelion, it is farther than the orbit of Mars.
With best regards, Filipp Romanov
