Optical spectroscopic observations of gamma-ray blazar candidates. X. Results from the 2018--2019 SOAR and OAN-SPM observations of blazar candidates of uncertain type

Optical spectroscopic observations of $γ$-ray blazar candidates VI. Further observations from TNG, WHT, OAN, SOAR and Magellan telescopes

Blazars, one of the most extreme class of active galaxies, constitute so far the largest known population of $γ$-ray sources and their number is continuously growing in the Fermi catalogs. However in the latest release of the Fermi catalog there is still a large fraction of sources that are classified as blazar candidate of uncertain type (BCUs) for which optical spectroscopic observations are necessary to confirm their nature and their associations. In addition about 1/3 of the $γ$-ray point sources listed in the Third Fermi-LAT Source Catalog (3FGL) are still unassociated and lacking an assi…

Optical spectroscopic observations of gamma-ray blazar candidates VIII: the 2016-2017 follow up campaign carried out at SPM, NOT, KPNO and SOAR telescopes

The third Fermi source catalog lists 3033 gamma-ray sources above $4σ$ significance. More than 30% are classified as either unidentified/unassociated Gamma-ray sources (UGSs), with about 20% classified as Blazar candidates of uncertain types (BCUs). To confirm the blazar-like nature of candidate counterparts of UGSs and BCUs, we started in 2012 an optical spectroscopic follow up campaign. We report here the spectra of 36 targets with observations from the Observatorio Astronómico Nacional San Pedro Mártir, the Southern Astrophysical Research Observatory, the Kitt Peak National Observatory and …

Optical detection of the black widow binary PSR J2052+1219

We present optical time-resolved multi-band photometry of the black widow binary millisecond pulsar J2052+1219 using direct-imaging observations with the 2.1m telescope of Observatorio Astronomico Nacional San Pedro Martir, Mexico (OAN-SPM). The observations revealed a variable optical source whose position and periodicity P = 2.752h coincide with the pulsar coordinates and the orbital period obtained from radio timing. This allowed us to identify it with the binary companion of the pulsar. We reproduce light curves of the source modelling the companion heating by the pulsar and accounting for…

亚利桑那大学SPOL光谱偏振仪的设备致宽

Instrumental Broadening Of The SPOL Spectropolarimeter At The University Of Arizona

本文利用对耀变体3C 273的多台站准同时光谱观测，估计了亚利桑那大学SPOL光谱偏振仪各狭缝宽度的设备致宽，发现不同孔径间存在显著差异，强调了逐孔径校正的必要性。

TEQUILA：用于天文学的无机械装置偏振测量法

TEQUILA: Mechanism-free polarimetry for astronomy

介绍用于墨西哥天文台1.3米望远镜的TEQUILA光学成像偏振计，用带片上线栅微偏振器阵列的CMOS传感器，无需移动光学部件同时测量斯托克斯参数，给出科学动机、设计等及初步科学结果。

Optical spectroscopic observations of low-energy counterparts of Fermi-LAT gamma-ray sources

A significant fraction of all $γ$-ray sources detected by the Large Area Telescope aboard the \fer\ satellite is still lacking a low-energy counterpart. In addition, there is still a large population of $γ$-ray sources with associated low-energy counterparts that lack firm classifications. In the last 10 years we have undertaken an optical spectroscopic campaign to address the problem of unassociated/unidentified $γ$-ray sources (UGSs), mainly devoted to observing blazars and blazar candidates because they are the largest population of $γ$-ray sources associated to date. Here we describe the o…