XLCALMASTR - XL-Calibur Master Catalog

Overview

This database table records high-level information for the observations obtained with the XL-Calibur experiment. The XL-Calibur is a balloon-borne second-generation (X-ray-focusing) Compton polarimeter operational in the energy range ~15-80 keV with the main objective to measure polarization in hard X-rays for a selection of bright sources.

XL-Calibur was successfully launched from the Esrange Space Center (Kiruna, Sweden) on July 9th, 2024 and following circumpolar winds in the west direction, the payload landed with a parachute near Kugluktuk (Canada) on July 14th. During operation, the Crab system (pulsar and wind nebula) and Cygnus X-1 black (X-ray binary system) were successfully observed. The data from these two sources were divided in observations roughly one day long.

An observation is defined as a collection of snap-shots where data are acquired on one specific on-source position alternate to an off-source position. The off source position data are used as background data. Each observation is labeled with a sequence number. The data associated includes event files for the on-source and off-source positions and three on-source spectra derived for the Stokes parameters I, Q, U, and an equivalent set for the off-source position. This database table contains one record for each sequence number and includes parameters related to the observation.

Catalog Bibcode

2025MNRAS.540L..34A

Bulletin

The XLCALMASTR database table was last updated on 8 August 2025.

References

XL-Calibur measurements of polarized hard X-ray emission from the Crab,
       Awaki, H. et al., 2025, Mon. Not. R. Astron. Soc., 540, L34-L40.
      =2025MNRAS.540L..34A

Provenance

The contents of this database table are generated at the HEASARC using information from the data files. The table was last updated in August 2025.

Parameters

ObsID
The unique number to identify an observation/sequence. This is a 10-digit number where the first 4 digits are for the year, the following 2 digits are for the source number and the last 4 digits identify a time interval of the observing timeline of data taken from a specific sky position.

Name
This is the designation of the pointed target as written in the event data file.

RA
Right Ascension of the source position as given in the event data file. The value is supplied with a precision of 10^-4 degrees.

Dec
Declination of the source position as given in the event data file. The value is supplied with a precision of 10^-4 degrees.

LII
Galactic longitude of the source position. This parameter is calculated from the J2000 pointing position.

BII
Galactic latitude of the source position. This parameter is calculated from the J2000 pointing position.

Time
The start time of the observation. This time corresponds to the earliest time either on-source or off-source included in the data. The value is supplied with a precision of 1 second.

End_Time
The time corresponding to the end of the observation. This time corresponds to the latest time either on-source or off-source included in the data. The value is supplied with a precision of 1 second.

Exposure_On_Src
Total exposure on source, in seconds, after data cleaning. The exposure is taken from the event file on source. The value is supplied with a precision of 10^-3 seconds.

Exposure_Off_Src
Total exposure off source, in seconds, after data cleaning. The exposure is taken from the event file off source. The value is supplied with a precision of 10^-3 seconds.

Num_Snapshot_On_Src
Number of snap-shots where the experiment was pointed on source within the start and stop of the observation.

Num_Snapshot_Off_Src
Number of snap-shots where the experiment was pointed on source within the start and stop of the observation.

Processing_Date
This parameter records the date when the data were last processed. The value is from the event file on source.

Processing_Version
This records the version of the processing script used in the pipeline to generate the data products for the observation.

Contact Person

Questions regarding the XLCALMASTR database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Friday, 08-Aug-2025 18:18:37 EDT