Results 71 to 80 of about 277 (132)

A New Phase of Optical Activity of BL Lacertae in the Fall of 2024: Intra-Night Flux and Polarization Variations

Universe
BL Lacertae is not only archetypical of an entire class of jet-dominated active galactic nuclei, blazars, but also one of the most active and rapidly changing objects in this class.
Rumen Bachev, Milen Minev, Anton Strigachev, Alexander Kurtenkov   +3 more
doaj   +1 more source

No evidence for radio-quiet BL Lacertae objects

The Astrophysical Journal, 1990
Using a large, flux-limited sample of faint X-ray sources, a search has been conducted for radio-quiet BL Lacertae objects. None has been found. Thirty-two X-ray-selected BL Lac objects and BL Lac candidates have been found within the sources of the Einstein Medium Sensitivity Survey (EMSS).
John T. Stocke, Simon L. Morris, Isabella Gioia, Tommaso Maccacaro, R. E. Schild, A. Wolter   +5 more
openaire   +1 more source

Investigating Optical Variability of the Blazar S5 0716+714 on Diverse Timescales

The Astrophysical Journal
We present the results of the observational study of the blazar S5 0716+716 in the optical bands B , V , R , and I between 2019 March and 2023 August to investigate its variability on diverse timescales.
Ergün Ege, Aykut Özdönmez, Aditi Agarwal, Tansel Ak   +3 more
doaj   +1 more source

H1517+656: The Birth of a BL Lacertae Object?

The Astrophysical Journal, 2005
H1517+656 is an unusual source, even for a BL Lac object. It is one of the most luminous BL Lac objects known, with extreme emission properties at radio, optical, and X-ray frequencies. Furthermore, in our WFPC2 snapshot survey we discovered a series of peculiar arcs describing a 24 radius ring surrounding the source.
O'Dowd, M., Urry, M., Scarpa, R., Wayth, Randall, Webster, R.   +4 more
openaire   +2 more sources

From Equipartition to Curvature: The Spectral Evolution of 4FGL Blazars

The Astrophysical Journal Supplement Series
We investigate the evolution of spectral energy distribution (SED) and underlying electron energy distribution (EED) by modeling the nearly simultaneous broadband spectra of selected bright 4FGL blazars, in the context of a combined cooling and ...
Muhammad S. Anjum, Shu-Jin Hou, Liang Chen, Zhigang Li, Minfeng Gu   +4 more
doaj   +1 more source

HST Observations of the Host Galaxies of BL Lacertae Objects

, 1998
23 pages, including 6 postscript figures and 3 tables (embedded). Latex requires aaspp4.sty and psfig.sty (not included).
URRY C. M., FALOMO R., SCARPA R., PESCE J. E., TREVES, ALDO, GIAVALISCO M.   +5 more
openaire   +3 more sources

Revisiting the Flaring Activity in Early 2015 of BL Lacertae Object S5 0716+714

The Astrophysical Journal
In this work, we analyzed multiwavelength data of the BL Lac object S5 0716+714 to investigate its emission mechanisms during a flaring state observed in early 2015.
Zhihao Ouyang, Hubing Xiao, Marina Manganaro, Shangchun Xie, Jingyu Wu, Jianzhen Chen, Rui Xue, Gege Wang, Shaohua Zhang, Junhui Fan   +9 more
doaj   +1 more source

The Remarkable Predictive Power of Infrared Data of Blazars

The Astrophysical Journal
Blazars are the brightest and most abundant persistent sources in the extragalactic γ -ray sky. Due to their significance, they are often observed across various energy bands, where the data of which can be used to explore potential correlations between ...
P. Giommi, N. Sahakyan, D. Israyelyan, M. Manvelyan   +3 more
doaj   +1 more source

A study of BL Lacertae objects [PDF]

Monthly Notices of the Royal Astronomical Society, 1980
K. W. Weiler, K. J. Johnston
openaire   +1 more source

Radio Detection of 18 RASS BL Lac Objects [PDF]

Serbian Astronomical Journal, 2009
We present the radio detection of 18 BL Lac objects from oursurvey of over 575 deg$^2$ of sky. These 18 objects are located within$20arcsec$ of the X-ray position, of which 11 have a measuredred-shift.
Anderson M. W. B., Filipović, M. D.
doaj