SN2024bch

General Information

• Name of the source: SN2024bch

• Brief description of the source:
  • Object type: CCSN type II-P/II-n
  • Distance (Mpc): 16.45
  • Redshift: 0.003839
  • Host galaxy: NGC 3206
  • RA: 10:21:49.740 (hh mm ss), Dec: +56:55:40.51 (dd mm ss)
  • RA, Dec in deg (ICRS): 155.45725, +56.927919

• Other relevant information and data:
  • Date of discovery: 2024-01-29 06:27:21
  • Date of explosion (inferred): 2024-01-28 14:38:24
  • Discovery report: https://www.wis-tns.org/object/2024bch/discovery-cert
  • Optical photometry: https://app.aavso.org/webobs/results/?star=000-BPV-330&num_results=200
  • Optical spectroscopy: https://www.wiserep.org/object/24751

People involved

Alphabetical order (corresponding authors)

• Arnau Aguasca-Cabot
• Alessandro Carosi
• Alicia López-Oramas
• Andrea Simongini (andrea.simongini@inaf.it)

Presentations

• 2024-06-21 LST Galactic group Meeting:
• 2024-06-10 LST Analysis Call: link to pdf
• 2024-05-21 LST General Meeting, Prague: link to pdf

Data-taking Information

• General information:
  • Start observation date: 2024-02-13
  • Total nights: 6
  • Total hours: 14.6
  • Total runs: 53
• Observation condition: moon and dark
• Observation mode: wobbles
• Joint observations with MAGIC?: yes (16845-16863)
• Joint analysis with MAGIC?: no

SN2024bch observations with LST-1

Run Number	Night	Run Start Time [UTC]	Run Elapsed Time [min]	Mean pointing zenith [deg]	Wobble Position	Used in stacked analysis	Conditions	ELOG
16771	20240213	00:29	20	32.6	W1	True	dark	20240213
16772	20240213	00:49	19	30.5	W2	True	dark	20240213
16773	20240213	01:08	24	29.9	W3	True	dark	20240213
16774	20240213	01:32	17	28.1	W4	True	dark	20240213
16775	20240213	01:49	20	xx	W1	True	dark	20240213
16776	20240213	02:09	20	xx	W2	True	dark	20240213
16777	20240213	02:29	20	28.9	W3	True	dark	20240213
16778	20240213	02:49	20	xx	W4	True	dark	20240213
16779	20240213	03:09	22	30.3	W1	True	dark	20240213
16780	20240213	03:31	19	32.5	W2	True	dark	20240213
16781	20240213	03:50	17	34.3	W3	True	dark	20240213
16803	20240214	01:11	26	29.3	W1	True	dark	20240214
16804	20240214	01:37	18	28	W2	True	dark	20240214
16805	20240214	01:55	15	28.5	W3	True	dark	20240214
16806	20240214	02:10	20	27.8	W4	True	dark	20240214
16807	20240214	02:30	23	28.5	W1	True	dark	20240214
16808	20240214	02:53	18	30	W2	True	dark	20240214
16809	20240214	03:11	20	31.4	W3	True	dark	20240214
16810	20240214	03:31	21	32.3	W4	True	dark	20240214
16811	20240214	03:52	4	34.4	W1	True	dark	20240214
16815	20240215	00:14	16	33.3	W1	False	dark	20240215
16816	20240215	00:30	20	31.4	W2	False	dark	20240215
16817	20240215	00:50	21	30.5	W3	False	dark	20240215
16818	20240215	01:11	21	28.7	W4	True	dark	20240215
16819	20240215	01:32	18	28.3	W1	True	dark	20240215
16820	20240215	01:50	20	28	W2	True	dark	20240215
16821	20240215	02:10	22	28.6	W3	True	dark	20240215
16822	20240215	02:32	19	28.5	W4	True	dark	20240215
16823	20240215	02:51	19	29.7	W1	True	dark	20240215
16824	20240215	03:10	22	31.9	W2	True	dark	20240215
16825	20240215	03:32	18	33.4	W3	True	dark	20240215
16826	20240215	03:50	12	34.6	W4	True	dark	20240215
16845	20240216	01:02	21	29.4	W1	False	dark	20240216
16846	20240216	01:23	20	28.3	W2	False	dark	20240216
16847	20240216	01:43	22	28	W3	False	dark	20240216
16848	20240216	02:05	19	27.8	W4	False	dark	20240216
16849	20240216	02:24	21	28.6	W1	True	dark	20240216
16850	20240216	02:45	20	29.9	W2	True	dark	20240216
16851	20240216	03:05	21	31.4	W3	True	dark	20240216
16852	20240216	03:26	20	32.5	W2	True	dark	20240216
16853	20240216	03:46	14	34.5	W3	True	dark	20240216
16863	20240218	03:10	19	32	W1	False	moon	20240218
16864	20240218	03:29	18	34.7	W2	False	moon	20240218
16866	20240218	03:47	19	36.1	W2	False	moon	20240218
16867	20240218	04:06	28	38.1	W3	False	moon	20240218
16868	20240218	04:25	3	xx	xx	False	moon	20240218
16869	20240218	04:34	19	41.1	W4	True	moon	20240218
16870	20240218	04:53	7	43.4	W1	True	moon	20240218
16980	20240306	00:15	20	28	W1	True	dark	20240306
16981	20240306	00:35	20	28	W2	True	dark	20240306
16982	20240306	00:55	20	28.7	W3	True	dark	20240306
16983	20240306	01:15	20	28.7	W4	True	dark	20240306
16984	20240306	01:35	8	30	W1	True	dark	20240306

Data quality cuts

We performed a standard source independent analysis for this source. The data quality is performed using the data_quality.ipynb notebook from the 2024-LST-School.

• Source selection:
  • zenith_range = [0, 90]
  • min_angle_to_source = 0.35
  • max_angle_to_source = 0.45
• Global cuts:
  • max_diffuse_nsb_std = 2.3
  • max_pointing_dec_std = 0.01
  • min_mean_fit_p = -3.
  • max_LS_periodogram_maxamplitude = 1e-2
  • min_drdi_index = -2.35
  • max_drdi_index = -2.1
  • min_drdi_at_422pe = 1.4
  • min_fraction_around_mode = 0.8
  • max_intensity_at_half_peak_rate = 70
• Data quality plots:

• Relative light yield of the selected nights:

• Results:
  • Good quality runs: 41/53(77%)
  • Total time: 12.1 h
• Extra notes:
  • 16868 is a very short run (3.4939323 min) due to data taking interruption by shifters
  • 16815 16816 16817 16847 16848 16867 were removed due to different NSB level

Data analysis

MC production

According to the data_quality.ipynb, the NSB level in the FoV of SN2024bch is low enough to consider the standard MC.

• MC used:
  • 20240131_allsky_v0.10.5_all_dec_base
• Declination line:
  • dec_6166 (4.8 deg away from SN 2024bch)

Pointing issues

We could not fit 3 OFF positions in several runs due to small offset angular distance of the wobbles.

• Possible solutions (applied in this analysis):
  • Reduce the max_theta_cut to 0.26 deg
  • Use only 1 OFF position

DL3 production

The DL3 are produced using the following standard parameters:

• Intensity cut: [50GeV, infty]
• w1: [0.01, 1]
• r: [0, 1]
• leakage_intensity_width_2: [0, 1]
• event_type: [32, 32]
• theta_containment: 0.7
• gh_efficiency: 0.7
• min_livetime: 300
• max_zenith: 90

DL3 data are stored here:

• /fefs/aswg/workspace/andrea.simongini/SN2024bch/DL3

Theta-squared plots

• We produced theta-squared plots with all good quality data:
  • n_wobbles: 4
  • theta2_cut: 0.04
  • energy bounds: [50GeV-100GeV]; [100GeV-1TeV]; [1TeV-10TeV]
  • gammaness_cut: 0.7
  • theta2_cut: 0.07 deg2
• Plots:

• Results:
  • [50GeV-100GeV]: N_on = 287155; N_off = 6220812; Significance = -0.572341
  • [100GeV-1TeV]: N_on = 107335; N_off = 2284060; Significance = -1.255360
  • [1TeV-10TeV]: N_on = 267; N_off = 6189; Significance = -1.701900