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We report optical Cousins R and I band monitoring observations of the high redshift (z = 4.67) QSO SDSS J153259.96-003944.1 that does not show detectable emission lines in its optical spectrum. We show this object varies with a maximum…
On ~1613 UT, 3 February 2022 SpaceX launched 49 Starlink satellites from Cape Kennedy, Florida into ~210 km altitude orbits where they were to receive subsequent boosts. We assume that 9 satellites received subsequent boosts and succeeded…
We revisit the Milky Way satellite problem using a semi-analytical model of galaxy formation and compare the predicted luminosity function to recent result from the SDSS. With cosmic photoionization, the luminosity function can be brought…
SpaceX recently proposed to orbit 19,440 Starlink internet satellites at a low altitude of 350 km instead of the current 550 km. The distribution in the sky and the apparent magnitudes of these spacecraft are simulated in this paper. During…
We present observations of 23 Starlink satellites in the $g'$ bandpass, obtained from the Dominion Astrophysical Observatory's Plaskett 1.8 metre telescope. The targets include a mixture of satellites with and without brightness mitigation…
CoRoT-3b is a 22 Jupiter-mass massive-planet/brown-dwarf object, orbiting an F3-star with a period of 4.3 days. We analyzed the out-of-transit CoRoT-3 red-channel lightcurve obtained by the CoRoT mission and detected the ellipsoidal…
We have monitored the quasar 3C 273 in optical $V$, $R$ and $I$ bands from 2005 to 2016. Intraday variability (IDV) is detected on seven nights. The variability amplitudes for most of nights are less than 10\% and four nights more than…
We present mid-infrared spectrophotometric results obtained with the ISO on the peculiar X-ray binary Cygnus X-3 in quiescence, at orbital phases 0.83 to 1.04. The 2.4-12 microns continuum radiation observed with ISOPHOT-S can be explained…
We report on optical-near-infrared photopolarimetric observations of a blazar 3C 454.3 over 200 d. The object experienced an optical outburst in July 2007. This outburst was followed by a short state fainter than $V=15.2$ mag lasting $\sim…
In this paper, we report the new results of spectroscopic observations of $\gamma$-ray blazar S5 0716+714 from 2019 September to 2020 March with the 2.4 m optical telescope at Lijiang Observatory of Yunnan Observatories. The median cadence…
We have searched the four brightest objects in the Kuiper belt for the presence of satellites using the newly commissioned Keck Observatory Laser Guide Star Adaptive Optics system. Satellites are seen around three of the four objects: Pluto…
We present very deep Wide Field Camera 3 (WFC3) photometry of a massive, compact galaxy located in the Hubble Ultra Deep Field. This quiescent galaxy has a spectroscopic redshift z=1.91 and has been identified as an extremely compact galaxy…
The quasar 3C279 was the target of an extensive multiwavelength monitoring campaign from January through April 2006, including an optical-IR-radio monitoring campaign by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper…
Aims. We aim to constrain the size and porosity of ejected dust particles from comet 252P/LINEAR and their evolution near the perihelion via near-infrared multiband polarimetry. A close approach of the comet to the Earth in March 2016…
CGRaBS J0809+5341, a high redshift blazar at z = 2.144, underwent a giant optical outburst on 2014 April 19 when it brightened by $\sim$5 mag and reached an unfiltered apparent magnitude of 15.7 mag. This implies an absolute magnitude of…
We report the discovery of a bright pulse having a dispersion measure (DM) equal to 134.4 \pm 2 pc cm^{-3}, a peak flux density (S_p) equal to 20 \pm 4 Jy and a half-width (W_e) equal to 211 \pm 6 ms. The excessive DM of the pulse, after…
A Time of Flight monitoring system has been developed for BES3. The light source is a 442-443 nm laser diode, which is stable and provides a pulse width as narrow as 50 ps and a peak power as large as 2.6 W. Two optical-fiber bundles with a…
In binary radio pulsar system J0737-3039, slow pulsar B shows orbital modulations of intensity, being especially bright at two short orbital phases. We propose that these modulations are due to distortion of pulsar B magnetosphere by pulsar…
We continuously monitored the blazar S5 0716+714 in the optical $g$, $r$ and $i$ bands from Nov. 10, 2017 to Jun. 06, 2019. The total number of observations is 201 nights including 26973 data points. This is a very large quasi-simultaneous…
The Be X-ray pulsar, SMC X-3 underwent a giant outburst from 2016 August to 2017 March, which was monitored with the Swift satellite. During the outburst, its broadband flux increased dramatically, and the unabsorbed X-ray luminosity…