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Observation Date (UT) Observation Lat

Canonical Name:RGB J2243+203
TeVCat Name:TeV J2243+203
Other Names:1FHL J2244.0+2020
VER J2243+203
Source Type:HBL
R.A.:22 43 52 (hh mm ss)
Dec.:+20 19 12 (dd mm ss)
Gal Long: 86.54 (deg)
Gal Lat: -33.39 (deg)
Flux:0.14 (Crab Units)
Energy Threshold:112 GeV
Spectral Index:4.6
Discovery Date:2014-12
Discovered By: VERITAS
TeVCat SubCat:Default Catalog

Source Notes:

This source was announced in an ATel by VERITAS on 141224

Source Position:
On 170920 the source position in TeVCat was updated from that given in
NED to that given by Abeysekara et al. (2017)
From Abeysekara et al. (2017):
- R.A. (J2000): 340.97 deg = 22h 43m 52s
- Dec. (J2000): +20.32 deg = 20d 19' 12''
- statistical uncertainty: 0.02 deg
- systematic uncertainty: 0.0007 deg
The coordinates are taken from NED:
- R.A. (J2000): 22 43 54.7
- Dec. (J2000): +20 21 04

Source Classification:
From Holder at al. (2014):
- "The source, classified as an intermediate-energy-peaked BL Lac
object in Laurent-Muehleisen et al. and a high-synchrotron-peaked BL
Lac object in the 1FHL catalog ..."

From Abeysekara et al. (2017):
- the integral flux above 112 GeV corresponds to 14% of the Crab flux
(Dec. 2014 observations)
From Holder at al. (2014):
- "Preliminary analysis shows the source to display a ~4% Crab Nebula
flux above 180 GeV."

Spectral Properties:
From Abeysekara et al. (2017):
- Spectral index: 4.6 +/- 0.5
From Abeysekara et al. (2015):
- Spectral index: 4.64 +/- 0.56

From Abeysekara et al. (2017):
- "On 21 and 23 December 2014, gamma-ray like events were detected
with a significance of 4.2 sigma in each day. No significant
detection of gamma-ray like events was recorded at the source location
on 22 and 24 December 2014."

From Gonzalez et al. (2018):
- "We present new spectroscopic data of the BL Lac RGB 2243+203, and
its surroundings, obtained with the OSIRIS Multi Object Spectrograph
(MOS) mounted in the Gran Telescopio Canarias (GTC). The spectra of
neither the BL Lac nor its host galaxy show any spectral feature, thus
hindering direct determination of its redshift. The spectroscopic
redshift distribution of objects in the MOS field of view shows four
galaxies with redshift between 0.5258 and 0.5288. We make use of a
statistical analysis to test the possibility that the targeted BL Lac
may be a member of that group. By using the spectroscopic redshifts
obtained with our GTC observations, we found that this probability is
between 86% and 93%."
From Abeysekara et al. (2017):
- "EBL model-dependent upper limits of the blazar redshift have been
derived. Depending on the EBL model used, the upper limit varies in
the range from z < 0.9 to z < 1.1"
From Meisner & Romani (2010):
- Redshift is z > 0.39

Seen by: VERITAS
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