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SWIFTBALOG - Swift BAT Instrument Log

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Overview

The BAT can operate several configuration modes simultaneously. Each of the simultaneous modes is listed in separate records within this table. For a given time interval, there are several records (partially overlapping in time), each describing a single configuration/mode. The BAT modes collect data for the entire FOV but also have the capability to record rates (tag mask rate) for up to a few specific sky positions (typically 3) that correspond to a pre-assigned target ID. It is possible that at least two or more of these positions do not coincide with the BAT or NFI pointing position and therefore the target ID does necessarily coincide with Target_ID of the BAT or NFI pointing position. This table records for the position (RA and Dec) and Target_ID parameters the correct values associated to each of the mask tag data.

Bulletin

The SWIFTBALOG database table was last updated on 19 October 2014.

Provenance

This database table is generated at the Swift processing site. During operation, it is updated on daily basis.

Parameters

Name
The designation of the pointed source. Note for the data taken with the mask tag rate or pulsar mode this field uses the name in the BAT catalog of the source being tagged instead of the pointing position.

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. Data taken in the BAT mask-tag configuration mode are associated with a specific source in the sky that may not necessarily be the main target of the observation. For these cases Orig_Target_ID parameter is set to the value pre-assigned to that source and differs from the value assigned to the main target of the observation.

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. Data taken in the BAT mask-tag configuration mode are associated with a specific source in the sky that may not necessarily be the main target of the observation. For these cases Target_ID parameter is set to the value pre-assigned to that source and differs from the value assigned to the main target of the observation.

RA
Right Ascension of the pointing position or position of the mask tag rate (or pulsar mode) source.

Dec
Declination of the pointing position or position of the mask tag rate (or pulsar mode) source.

Roll_Angle
Roll angle of the observation given in degrees.

Start_Time
Start time of this BAT instrument configuration.

Stop_Time
Stop time of this BAT 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_Number 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 for the current record.

Ratecode
This parameter records which of the BAT rate data modes are available for this time interval. Note this flag is only valid if the Operation_Mode parameter is set to "Rate_Arr_1s."

The BAT operates the rate modes simultaneously. These are the 1-sec, 64-ms, 1.6-sec, and the max rates. This database reports the information only for the 1-sec rate, but records in this parameter if any of the other rates are simultaneously working. The parameter is made of 4 digits, where each can assumed value of 0 or 1. The first digit is for the 1-sec rate, the second is for the 64-ms rate , the third is for the 1.6-sec rate and the last is for the maxrate. If all rate modes are present within the interval, the parameter is set to "1111". If instead the 64-ms is not present, the parameter is "1011". For all other operating modes, this parameter is blank.

Catnum
This parameter contains the BAT catalog number corresponding to the sky position used in the mask tag rate or the pulsar mode. For all other modes this is set to 0. The value of the BAT catalog number is assigned using the Target_Id value.

Operation_Mode
This parameter contains the operation mode running within the start and stop listed for the current record. The BAT can operate simultaneously several modes where each mode can start and end at different times.

Pointing_Mode
This parameter contains the spacecraft observing mode.

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

LII
The Galactic Longitude of the pointing position or position of the mask tag rate (or pulsar mode) source. Note that the pointing position can be different from the GRB (or other target) position.

BII
The Galactic Latitude of the pointing position or position of the mask tag rate (or pulsar mode) source. Note that the pointing position can be different from the GRB (or other target) position.


Contact Person

Questions regarding the SWIFTBALOG database table can be addressed to the HEASARC User Hotline.

Page Author: Browse Software Development Team
Last Modified: 5-Mar-2012