Analysis OP313 Dec 2023 ToO

General information

• Name of the source: OP313
• Brief description of the source:

- Object type : FSRQ

- Redshift : z=0.997 (Schneider et al. 2010, AJ, 139, 2360)

Atel

• https://www.astronomerstelegram.org/?read=16381

The Large-Sized Telescope (LST-1) on La Palma has been monitoring the very distant Flat Spectrum Radio Quasar (FSRQ) OP 313 (z=0.997, Schneider et al. 2010, AJ, 139, 2360) 
since November 2023. Following the announcement of enhanced gamma-ray emission by Fermi-LAT (ATel #16356) and several optical facilities (ATel #16360) in early December, 
the Fermi-LAT emission of OP 313 has been closely monitored using the FlaapLUC pipeline (Astronomy and Computing, Volume 22, p. 9-15, 2018). This monitoring revealed the 
detection of renewed activity in the high-energy (HE, E>100 MeV) band and so, Target of Opportunity observations with LST-1 were triggered on December 10th 2023. OP 313 
was detected by LST-1 with a preliminary offline analysis using data from 2023/12/11 to 2023/12/14. It was detected with a significance greater than 5 sigma and an integrated 
flux, above 100 GeV, at 15% flux of the Crab Nebula. LST-1 observations on OP 313 will continue during the next few nights and therefore multi-wavelength observations are highly 
encouraged. LST-1 is a prototype of the Large-Sized Telescope for the Cherenkov Telescope Array Observatory, and is located on the Canary island of La Palma, Spain.
The telescope design is optimized for observation of gamma rays in the range from 20 GeV to 3 TeV. The preliminary offline analysis has been performed by Daniel Morcuende (dmorcuende@iaa.es),
Jorge Otero-Santos (joteros@iaa.es) and Seiya Nozaki (nozaki@mpp.mpg.de). The LST-1 contact persons for these observations are Masahiro Teshima (mteshima@mpp.mpg.de) and Juan Cortina (juan.cortina@ciemat.es).

Data-taking information

• observation summary

Date	Runs	time (h)	Zd	Az	Transmission	Comments
2023-12-09	15942, 15943, 15944, 15945	1.31	35-53	-	-	50-sec shifted timestamp
2023-12-10	15973, 15974, 15975, 15976, 15977, 15978	1.61	30-51	-	-
2023-12-11	16007, 16008, 16009, 16010, 16011	1.39	30-54	-	-
2023-12-12	16042, 16043, 16044, 16045, 16046	1.63	30-54	-	-
2023-12-13	16079, 16080, 16081, 16082, 16083	1.69	30-53	-	-
2023-12-14	16114, 16115, 16116, 16117, 16118, 16119	1.60	30-52	-	-
2023-12-15	16150, 16151, 16152, 16153, 16154, 16155, 16156, 16157	1.75	30-52	-	-
2023-12-16	16188, 16189, 16190, 16191, 16154, 16192, 16193			-	-
2023-12-17	16220, 16221, 16222, 16223, 16224, 16225			-	-

Fast Analysis (Daniel Morcuende)

Src-independent analysis, Gammaness cut efficiency of 40%, Theta containment 70%, 3 OFF positions, theta2 cut at 0.04 deg2

Fast Analysis (Jorge Otero)

Standard MC dark analysis

• Theta2 plots
  • 10-14 December

Energy dependent cuts: 0.6gh efficiency, 0.7theta efficiency

energy dependent cuts (0.6gh efficiency, 0.7theta efficiency), interpolated IRFs

• • 11-14 December

Global fixed cuts: 0.7 gammaness, 0.2 theta

global fixed cuts (0.7 gammaness, 0.2 theta), interpolated IRFs

• • All data stacked (10-17 December)

• Lightcurve
• SED

Fast Analysis (Seiya Nozaki)

• 2023-12-10
  • run 15973, 15974, 15975, 15976, 15977, 15978
  • standard MC (dark)

intensity>50, gammaness>0.7

File:OP313 20231210 srcdep g08 i150 Nozaki.png intensity>150, gammaness>0.8

• 2023-12-11
  • run 16007, 16008, 16009, 16010, 16011
  • standard MC (dark)

intensity>50, gammaness>0.7

intensity>50, gammaness>0.7 (stacked)

File:OP313 20231211 srcdep g08 i150 Nozaki.png intensity>150, gammaness>0.8

• 2023-12-12
  • run 16042, 16043, 16044, 16045, 16046
  • standard MC (dark)

intensity>50, gammaness>0.7

intensity>50, gammaness>0.7 (stacked)

File:OP313 20231212 srcdep g08 i150 Nozaki.png intensity>150, gammaness>0.8

• 2023-12-13
  • run 16079, 16080, 16081, 16082, 16083
  • standard MC (dark)

intensity>50, gammaness>0.7

intensity>50, gammaness>0.7 (stacked)

intensity>150, gammaness>0.8

• 2023-12-14
  • run 16114, 16115, 16116, 16117, 16118, 16119
  • standard MC (dark)

intensity>50, gammaness>0.7

File:OP313 20231214 srcdep g07 i50 stacked Nozaki.png intensity>50, gammaness>0.7 (stacked)

File:OP313 20231214 srcdep g08 i150 Nozaki.png intensity>150, gammaness>0.8

• 2023-12-15
  • run 16150, 16151, 16152, 16153, 16154, 16155, 16156, 16157
  • standard MC (dark)

intensity>50, gammaness>0.7

intensity>50, gammaness>0.7 (stacked)

intensity>50, gammaness>0.6

Fast Analysis (Joshua Baxter)

• 2023-12-14
  • Run Number: [16114, 16115, 16116, 16117, 16118, 16119]

gamma efficiency = 50 %, theta = 68 %

• 2023-12-15
  • Run Number: [16150, 16151, 16152, 16153, 16154, 16155, 16156, 16157]

gamma efficiency = 50 %, theta = 68 %

intensity>50, gamma efficiency = 50 % (Dec 14-15th 2 days stacked)

intensity>50, gamma efficiency = 50 % (Dec 14th)

intensity>50, gamma efficiency = 50 % (Dec 15th)

• 2023-12-16
  • Run Number: [16187, 16188, 16189, 16190, 16191, 16192, 16193]

gamma efficiency = 50 %, theta = 68 %

intensity>50, gamma efficiency = 50 % (Dec 16th)

intensity>50, gamma efficiency = 50 % (Dec 14th-16th 3 days stacked)