AC2026OSJ at 13.3 ( instead of ~19)

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1

Dear all,

Tonight ( 26june2026), I had a 2hours exposure ( Gaia Clear Filter) with a C14 .

4FGL J1422.5+3223, astrocolibi ID AC 2026osj ( FlaapLUC / Fermi-LAT) expected to catch a faint glow from this object

( At this coordinate, simbad is providing this : ICRF J142230.3+322310

and MASTER OT J142230.38+322310.6 )

It appears that the object was measured at mag 13.3 .

The object is easely visible on 60s single exposure.

AC2026OSJ_visu3
AC2026OSJ_visu3642×504 135 KB

AC2026OSJ_visu2
AC2026OSJ_visu2771×576 138 KB

AC2026OSJ_visu1
AC2026OSJ_visu11004×695 84.2 KB

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2

Hi!

Congrats!

For context: FlaapLUC / Fermi-LAT alerts are denoting flares of high-energy gamma-rays. In this case, the gamma-rays are associate to a Seyfert Galaxy at a redshift of z=0.681 as identified via your SIMBAD search.
Monitoring of these objects during their flaring phases would provide interesting scientific information (e.g. we can study the correlations between the optical and gamma-ray emission, etc.). Maybe the weather (and your time) allows for that?

3

Hi,

>Maybe the weather (and your time) allows for that?

I got storm this night :frowning: :cloud_with_rain:

4

Follow up by 9 July 2026 :

Using RAPAS filter, A

AC2026OSJ_color
AC2026OSJ_color1481×954 374 KB

AC2026osj has been measured with following results :

09/july/2026 - 21:07:41.820 Mag G : 12.7 +/- 0.05

09/07/2026 - 21:13:33.010 Mag Gbp : 13.18 +/- 0.06

09/07/2026 - 21:19:05.410 Mag Grp : 12.1 +/- 0.2 1

5

Follow up 12 july 2026, 23h30TU

Using RAPAS Star’ex_VLR ( R=200) spectrograph a 2h exposure has been performed on a d=150mm f=750mm newton, providing a clear spectra of the source ( even if strong light pollution and atmospheric emission/absorption are visible).

AC2026osj_12juillet2026_23h30_1
AC2026osj_12juillet2026_23h30_11377×169 44.2 KB

The resulting spectra appears very flat, without emission lines, and unfortunately, do not provide specific information.

ac2026osj_12juillet2026_23h30_graph_1
ac2026osj_12juillet2026_23h30_graph_1753×555 4.66 KB

Michael

Note :
Field of spectrograph guider :

spectro_field_of_AC2026osj
spectro_field_of_AC2026osj987×747 182 KB

6

Congrats!
The flat, featureless spectrum is expected for this kind of sources: it is dominated by synchrotron radiation from high-energy relativistic electrons spiraling around magnetic fields in the jet. The blazar is still in an excited state (see the gamma-ray lightcurve in Astro-COLIBRI, so the jet emission dominates over the host galaxy.
As mentioned, monitoring of the flux and spectral evolution continues to be interesting because one could correlate it with the gamma-ray emission.

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