Blazar PKS 1424-414 (z=1.522) brightening

Blazar PKS 1424-414 (z=1.522) brightening

Postby Terry Bohlsen » Wed Jul 27, 2022 8:54 am

Hi All
There was a recent ATel #15525 reporting a brightening of this very distant object up to a mag of R=13.4
I tried to take a spectrum of it using my LISA. It is pretty dim but I could certainly obtained a spectrum. It seems pretty flat but because of the high redshift it is difficult for me to determine even vague lines.
Certainly a z=1.522, this is the furthest out object I have been able to take a spectrum of.

Terry
pks1424-418_20220725_452_TBohlsen.png

PKS1424 418pointing_small.png
PKS1424 418pointing_small.png (545.46 KiB) Viewed 454 times

PKS1424 418guider.jpg



Posted: Within the last 24 hours
==============================================================================
ATEL #15525 ATEL #15525

Title: Bright optical/GeV-ray flares in Blazars PKS 1424-418 and PKS
1406-076
Author: F. Jankowsky, S. J. Wagner, F. Ait-Benkhali (LSW Heidelberg)
Queries: swagner@lsw.uni-heidelberg.de
Posted: 23 Jul 2022; 23:10 UT
Subjects:Optical, Gamma Ray, >GeV, AGN, Blazar, Quasar

Optical observations of the PKS 1424-418 (z=1.522, White et al., ApJ, 327,
561 (1988)) with the Automatic Telescope for Optical Monitoring (ATOM)
in Namibia reveal this Blazar in a bright optical state. Preliminary analysis
of measurements performed on July 23 2022 (MJD 59783.8) show a peak R
magnitude of 13.4 with 0.1 mag variations within one hour. This is 4.6
magnitudes brighter than the
lowest flux measured during the last 15 years. PKS 1424-418 underwent a
steady increase in brightness by 1.2 magnitudes since July 15, 2022 (MJD
59775.2). The optical flare is 0.9 mag brighter than an earlier outburst
observed in May 2010, with a coincident GeV Gamma-ray flare (ATEL #2613,
Buson et al., AA 569, A40 (2014)).

The flare observed in the optical band coincides with an increase of gamma-ray
flux recorded in the 100 MeV - 500 GeV band with the Fermi-LAT instrument
reaching a level of 3.5 10<sup>-6</sup> cm<sup>-2 </sup> s<sup>-1</sup>
on July 22 2022, exceeding the flux of the 2013 flare which has been
the brightest flare in the LAT band so far.

Optical observations of the Blazar PKS 1406-076 (z=1.494, Wilkes et al.,
PASA, 5, 2 (1983)) with ATOM show this Blazar in a bright optical state.
Preliminary analysis of measurements performed on July 23 2022 (MJD 59783.8)
show a peak R magnitude of 16.2. This is 3 magnitudes brighter than the
lowest flux measured during the last 15 years. PKS 1406-076 underwent a
steady increase in brightness by 1.7 magnitudes since May 24, 2022 (MJD
59723.8). This is the brightest flare recorded with ATOM during the past
15 years.

Further multi-frequency observations of these outbursts are encouraged.

ATOM is a 75cm optical telescope located at the H.E.S.S. site in Namibia.

Fermi-LAT fluxes are available also on the public LAT light curve page.
Terry Bohlsen
Armidale NSW
Australia
Terry Bohlsen
 
Posts: 191
Joined: Thu Sep 29, 2011 7:40 am

Re: Blazar PKS 1424-414 (z=1.522) brightening

Postby Hamish Barker » Wed Jul 27, 2022 9:01 pm

Nice work Terry.

It is certainly a bit mind boggling to be able to measure something so far away, and to do it with amateur equipment is even more incredible.

If 2SPot is able to take a spectrum with a slightly wider wavelength range by a few hundred angstrom each way, there are two possible absorbtion lines just off both the blue and red ends which were previously used to obtain the indicated redshift measurement.
Hamish Barker
 
Posts: 211
Joined: Thu Jun 20, 2019 12:11 am


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