SWIFTXRLOG - Swift XRT Instrument Log

Overview

The XRT runs only one type of configuration mode/window in a given time interval. The table therefore contains for a given time interval a single record that describes one configuration. A new record is generated when the following is changing within an observation: new operating mode , new pointing mode, or new window configuration.

Bulletin

The SWIFTXRLOG database table was last updated on 30 October 2025.

Provenance

This database table is generated by the Swift Data Center. During operation, it is updated on daily basis.

Parameters

Name
The designation of the pointed source.

Orig_Target_ID
This is a numerical value assigned automatically to each target and corresponds to the trigger number. The numerical value follows the convention adopted for Swift to assign the target identification. The numerical values can include up to 8 digits.

Target_ID
This is a unique numerical value assigned to each target and corresponds to the unique trigger number. To remove the degeneracy in the assignment of Target_ID for the safe pointing position and/or to correct any wrong assignment of the Target_ID, the unique (or the correct) number is re-assigned on ground and stored in the True_Target_ID parameter. In these cases Orig_Target_ID and Target_ID do not contain the same values otherwise they are identical. The numerical value follows the convention adopted for Swift to assign the target identification. The numerical values can include up to 8 digits.

RA
Right Ascension of the pointing position or position of the mask tag rate source.

Dec
Declination of the pointing position or position of the mask tag rate source.

Roll_Angle
Roll angle of the observation given in degrees.

Start_Time
Start time for this XRT instrument configuration.

Stop_Time
Stop time for this XRT instrument configuration.

Orig_Obs_Segment
The Swift observation strategy is similar to a monitoring campaign, where a target is observed several times. The observation segment, stored in this parameters, corresponds to the number of times a specific target has been observed. The numerical value follows the convention adopted for Swift to assign the observation segments and can include up to 3 digits.

Obs_Segment
This parameter contains the correct observation segment. The Swift observation strategy is similar to a monitoring campaign, where a target is observed several times. The observation segment, stored in this parameters, corresponds to the number of times a specific target has been observed. The numerical value follows the convention adopted for Swift to assign the observation segments and can include up to 3 digits. However the observation segment value can be wrongly assigned. This parameter contains the correct value reassigned on ground.

Orig_ObsID
This parameter contains a numeric value that should uniquely identify an observation. This value is the combination of the numerical value assigned to a target and the observation segment and is derived from the parameters Orig_Target_ID and Orig_Obs_Segment. Since the latter can be wrong or not unique the Orig_Obs_Numberf can also be wrong or not unique. The numerical value is a fixed 11-digit number, where the first 8 are for the target and last 3 are for the observation segment. Note that the Target_ID used in the observation number is the value associated to the current pointing position and not to the pre-assigned mask task rate listed in the Target_ID parameter in this table.

ObsID
This parameter contains a numeric value that uniquely identifies an observation. This value is the combination of the numerical value assigned to a target and the observation segment and is derived from the parameters Target_ID and Obs_Segment. The numerical value is a fixed 11-digit number, where the first 8 are for the target and last 3 are for the observation segment. Note that the Target_ID used in the observation number is the value associated to the current pointing position and not to the pre-assigned mask task rate listed in the Target_ID parameter in this table. The data directory is named after the ObsID.

Exposure
Total exposure time in seconds for the data included in the current record.

Integration_Time
Integration time given in seconds. This is changing with the data mode.

Window_Size
Indicates the window size used during this time interval. This parameter is relevant only for the Windowed Timing and Photon Counting modes. In all other cases, it is set to NA (not applicable).

Ccdtemp
Gives the average temperature of time interval included in the current record. Note that, if the flipflop flag is set to Y, the average temperature is calculated on time intervals where another mode is running.

Bias
This flag indicates whether or not the bias has been subtracted on-board. For the Photodiode (Piled-up or Low Rate) and Image modes, the bias can be either subtracted on-board or not. For Windowed Timing and Photon Counting modes, the bias is always subtracted on-board, while for the Raw frame and Bias mode, it is never subtracted. The value of the parameter is Y (bias subtracted on-board) or N.

Operation_Mode
This parameter contains the operation mode running within the start and stop listed for the current record.

Pointing_Mode
This parameter contains the observing mode of the spacecraft. The values are "pointing","settling" or "slew".

Filename
Name or root for the file containing the data for this interval.

Flipflop
The XRT modes change automatically depending on the flux recorded. A flip-flop between modes has been observed from time to time when there is a highly variable background due to flickering pixels or the bright Earth. This parameter indicates if within the current interval a flip-flop is observed. The other mode involved in the flip-flop is in a separate record that partially overlaps in time with the current. The value of the parameter is Y (flip-flop occurred) or N.

LII
Galactic Longitude of the pointing position. Note that the pointing position can be different from the GRB (or other target) position.

BII
Galactic Latitude of the pointing position. Note that the pointing position can be different from the GRB (or other target) position.

Contact Person

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

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:35:35 EDT