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).

Meeting

Kickoff meeting (19 Jan 2024): https://indico.cta-observatory.org/event/5330/
meeting 02 February 2024: https://indico.cta-observatory.org/event/5379/
meeting 16 February 2024: https://indico.cta-observatory.org/event/5412/

Data-taking information and data quality selection

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 -> solved!
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	-	-	No tracking during run 16157
2023-12-16	16188, 16189, 16190*, 16191, 16192, 16193	1.67	25-52	-	-	Drive issue during run 16190 (no tracking)
2023-12-17	16220, 16221, 16222, 16223, 16224, 16225	1.72	25-50	-	-
2023-12-18	16240, 16241, 16242, 16243, 16244, 16246		25-50	-	-	online gain-selected data
2023-12-19	16258, 16259, 16260, 16261, 16262, 16263		25-50	-	-	online gain-selected data
2023-12-20	16269, 16270		40-43	-	-	online gain-selected data, humidity is rising during run 16270
2024-01-09	16293, 16294, 16295	0.63	20-26	-	-
2024-01-13	16350, 16351, 16352, 16353, 16354, 16355, 16356, 16357, 16358, 16359	2.08	15-43	-	-
2024-01-17	16391, 16392	0.46	25-30	-	-	Timestamp is shifted?? -> solved!
2024-01-18	16407	0.10	4-6	-	-
2024-01-19	16412, 16413, 16414, 16415	1.34	5-30	-	-
2024-01-21	16418, 16419, 16420	0.70	4-8	-	-

Analysis 1 (Daniel Morcuende)

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

Analysis 2 (Jorge Otero)

Standard MC dark analysis

-Zd~15-54 deg

-MC prod: 20230901_v0.10.4_allsky_base_prod/…/dec_3476

Theta2 plots

Energy dependent cuts: 0.7gh efficiency, 0.7theta efficiency 
(maximum theta cut restricted to 0.2 to avoid ON-OFF overlapping in post-DL3 analysis)

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs (all Dec.+Jan. data)

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, high state (Dec. 2023)

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, low state (Jan. 2024)

Different energy bins:

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

Nightwise theta2 plots:

2023-12-09, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-10, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-11, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-12, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-13, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-14, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-15, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-16, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-17, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2023-12-18, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2024-01-09, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2024-01-13, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2024-01-17, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2024-01-19, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

2024-01-21, energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

SED

Assuming a PWL+EBL spectral model (Saldana-Lopez 2021 EBL model):

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, high state (Dec. 2023)

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, low state (Jan. 2024)

Lightcurve

Complete lightcurve above 100 GeV assuming the SED obtained for the high state in December 2023:

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs

Average flux:
F=(4.69 土 0.10)・10e-11 cm-2 s-1 = 10% Crab Nebula flux

Separating high and low state:

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, high state (Dec. 2023)

energy dependent cuts (0.7 gammaness, 0.7 theta), interpolated IRFs, low state (Jan. 2024)

Average flux for the high state:
F=(1.35 土 0.19)・10e-10 cm-2 s-1 = 28.3% Crab Nebula flux

Fast Analysis (Seiya Nozaki)

2023-12-09
- run 15942, 15943, 15944, 15945
- standard MC (dark)

intensity>50, gammaness>0.7

intensity>150, gammaness>0.8

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

2023-12-16
- run 16188, 16189, 16190, 16191, 16192, 16193
- standard MC (dark)

intensity>50, gammaness>0.7

File:OP313 20231216 srcdep g07 i50 stacked Nozaki.png

intensity>50, gammaness>0.7 (stacked)

2023-12-17
- run 16220, 16221, 16222, 16223, 16224, 16225
- standard MC (dark)

intensity>50, gammaness>0.7

File:OP313 20231217 srcdep g07 i50 stacked Nozaki.png

intensity>50, gammaness>0.7 (stacked)

2024-01-09
- run 16293, 16294, 16295
- standard MC (dark)

intensity>50, gammaness>0.7

File:OP313 20240109 srcdep g07 i50 stacked Nozaki.png

intensity>50, gammaness>0.7 (stacked)

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)

Fast Analysis (Elisa Visentin)

Joint runs: 2023/12/09, 2023/12/10, 2023/12/11, 2023/12/14, 2023/12/15, 2023/12/16, 2023/12/17, 2023/12/18, 2024/01/09

gamma efficiency 90%, theta cut 0.2 deg, MAGIC intensity > 30 pe, LST intensity > 50 pe Data selection: LST runs where > 3 minutes of stereo joint data taking