DA 193
Blazar in the constellation Auriga
From Wikipedia, the free encyclopedia
DA 193 is a blazar[1] located in the constellation of Auriga. It has a high redshift of 2.365.[2][3] It was first discovered as an unknown astronomical radio source in 1971 by D.G. MacDonell and A.H. Bridle.[4] This is a low polarized quasar[5] containing a classic homogeneous synchrotron self-absorption spectrum.[6] The radio spectrum of this source shows a turnover frequency at 5 GHz[5] and this object has also been referred to as a gigahertz-peak spectrum source.[7][8]
| DA 193 | |
|---|---|
The blazar DA 193 | |
| Observation data (J2000.0 epoch) | |
| Constellation | Auriga |
| Right ascension | 05h 55m 30.805s |
| Declination | +39° 48′ 49.165″ |
| Redshift | 2.365000 |
| Heliocentric radial velocity | 709,009 km/s |
| Distance | 10.545 Gly |
| Apparent magnitude (V) | 18.3 |
| Characteristics | |
| Type | Blazar |
| Other designations | |
| SWIFT J0555.5+3946, WMAP 100, TXS 0552+398, 2XMM J055530.7+394848 | |
DA 193 is found variable on the electromagnetic spectrum. It is bright in X-rays and displays a flat X-ray spectrum that is above 10 keV. During the first week of January 2018, it underwent a giga-electron volt (GeV) flare which was detected by Fermi-LAT.[9] This GeV flare exhibited from DA 193 showed an exceeded binned gamma ray flux (1 × 10−6 ph cm−2 s−1) and was found to be extremely luminous (Lγ = (1.3 ± 0.4) × 1050 erg s−1). When observing its hard gamma-ray spectrum, the flare in DA 193 was confirmed to be a rare sight. In the optical-X-ray energy range, it shows an insignificant flux meaning its source went back to its quiescence state.[10]
DA 193 contains one of the most compact radio sources known on both millisecond and arcsecond scales.[2] In its radio structure, there are four components in the core region with the suggestion of a weak component located 2.3 mas. There is presence of a short jet extending towards the western direction.[11] Furthermore, DA 193 has a simple core-halo structure according to VLBI Observations, with the major axis of the halo having a 110° position angle. This halo's position angle is found alike to the linear polarization position angle.[5]
The central supermassive black hole of DA 193 is estimated to be (5.5 ± 0.9) × 109 M☉ based on calculations of a single optical spectroscopic emission line information, derived from usage of C IV emission lines and acquiring empirical relations proposed by Yue Shen. Its accretion disk luminosity is estimated as (1.3 ± 0.1) × 1047 erg s−1.[10]
DA 193 has one close companion 2.9" to the north. The companion is found connected to the quasar via tidal interactions. Both objects are situated in a dense compact galaxy group.[8][12]