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BBXRT: Help

BBXRT - BBXRT Archive


Overview

The BBXRT database table contains information about each observation made by the Broad Band X-Ray Telescope. It includes a catalog of observations and spectral and lightcurve products for each of the 10 pixels per observation.

Catalog Bibcode

1995ApJS...96..303W

Description

The Broad Band X-Ray Telescope (BBXRT) was part of the ASTRO-1 mission which flew on the Space Shuttle Columbia December 2-10, 1990. The BBXRT instrument has 2 co-aligned telescopes with a 3.8-meter focal length. Each telescope contains a mirror assembly consisting of 118 curved, gold-plated aluminum reflectors, and a cryogenically cooled Si(Li) detector at the focal plane. Each detector is divided into 5 pixels; the central pixel has a 4 arcminute field of view, and the outer pixels extend the total field of view to 17 arcminutes. The effective energy range is 0.3-12 keV, with an energy resolution of approximately 150 eV at 6 keV.

The BBXRT observing program consisted of an even mix of galactic and extragalactic sources, although the galactic center, containing many prime targets, was unavailable due to the proximity of the sun in early December. BBXRT performed 157 observations of 82 celestial sources (note that we have defined a single pointing with a pointing "tweak" in the middle as two observations).


Parameters

Name
The name of the target.

RA
The Right Ascension of the target in hh mm ss.

Dec
The Declination of the target in deg mm ss.

LII
The Galactic Latitude of the target in decimal degrees.

BII
The Galactic Longitude of the target in decimal degrees.

Roll
The shuttle roll angle in decimal degrees.

Time
The start time of the observation (yy/dd hh:mm).

End_Time
The end time of the observation (yy/ddd hh:mm).

Exposure
The exposure time of the observation in seconds.

Daynight
Shuttle day/night indicator: N = night, D = day, MN = mostly night (>75%), MD = mostly day (>75%), B = both, mixed.

Data_Rate
The rate at which data was obtained where M = medium (64 kbs), L = low (1.5 or 16 kb/s).

Saa
If `Y`, the observation contains electron contamination from an SAA passage. `N` indicates otherwise.

Sequence_Number
BBXRT sequence number. Numbers were assigned in time order.

Type
Object type.

Ara
Aspect camera solution for Right Ascension for pointing position. When no solution is available, the ARA is set to:

     -1 = camera off;
     -2 = camera on, but no solutions obtained, i.e., field was flooded with
          light, too sparse, too crowded for solution, or there was an
          instrumental problem;
     -3 = 'slew observation', no stable pointing.
  

Arasd
Standard Deviation of aspect camera solution for Right Ascension.

Adec
Aspect camera solution for Declination for pointing position.

Adecsd
Standard Deviation of aspect camera solution for Declination.

Aroll
Aspect camera solution for shuttle roll for pointing position.

Arollsd
Standard Deviation of aspect camera solution for shuttle roll.

Offset
Off-axis angle in arcminutes, as derived from the nominal RA/Dec and Aspect Camera RA/Decs. Where Offset is non-zero but no ARA and ADec are zero, the Offset is derived from ray tracing.

A0_Count_Rate
The counts/second in each pixel (A0 - B4) over the energy range 0.3 - 12 keV. The A0 and B0 pixels are circular central pixels on the A and B telescopes, respectively. The A1 - A4 and B1 - B4 pixels are outer pixels on each telescope.

A0_Count_Rate_Error
The error in counts/sec on the count rate for each corresponding pixel.

A1_Count_Rate
The counts/second in each pixel (A0 - B4) over the energy range 0.3 - 12 keV. The A0 and B0 pixels are circular central pixels on the A and B telescopes, respectively. The A1 - A4 and B1 - B4 pixels are outer pixels on each telescope.

A1_Count_Rate_Error
The error in counts/sec on the count rate for each corresponding pixel.

A2_Count_Rate
The counts/second in each pixel (A0 - B4) over the energy range 0.3 - 12 keV. The A0 and B0 pixels are circular central pixels on the A and B telescopes, respectively. The A1 - A4 and B1 - B4 pixels are outer pixels on each telescope.

A2_Count_Rate_Error
The error in counts/sec on the count rate for each corresponding pixel.

A3_Count_Rate
The counts/second in each pixel (A0 - B4) over the energy range 0.3 - 12 keV. The A0 and B0 pixels are circular central pixels on the A and B telescopes, respectively. The A1 - A4 and B1 - B4 pixels are outer pixels on each telescope.

A3_Count_Rate_Error
The error in counts/sec on the count rate for each corresponding pixel.

A4_Count_Rate
The counts/second in each pixel (A0 - B4) over the energy range 0.3 - 12 keV. The A0 and B0 pixels are circular central pixels on the A and B telescopes, respectively. The A1 - A4 and B1 - B4 pixels are outer pixels on each telescope.

A4_Count_Rate_Error
The error in counts/sec on the count rate for each corresponding pixel.

B0_Count_Rate
B0 Count Rate

B0_Count_Rate_Error
B0 Count Rate Error

B1_Count_Rate
B1 Count Rate

B1_Count_Rate_Error
B1 Count Rate Error

B2_Count_Rate
B2 Count Rate

B2_Count_Rate_Error
B2 Count Rate Error

B3_Count_Rate
B3 Count Rate

B3_Count_Rate_Error
B3 Count Rate Error

B4_Count_Rate
B4 Count Rate

B4_Count_Rate_Error
B4 Count Rate Error

Count_Rate
The sum of the count rates of all 10 pixels of the BBXRT telescopes.

Count_Rate_Error
The error in counts/sec on the total Count_Rate.

A_Ratio
A string of 5 numbers which show the relative countrates in each pixel (A0, A1, A2, A3, A4) compared to the total count rate for the A telescope. Each digit multiplied by 10 gives the percentage of the counts in that pixel.

B_Ratio
A string of 5 numbers which show the relative countrates in each pixel (B0, B1, B2, B3, B4) compared to the total count rate for the B telescope. Each digit multiplied by 10 gives the percentage of the counts in that pixel.

File_Spectrum
The filename root of the 10 spectra (one from each pixel). This is also the filename root of the 10 light curves.

Response_Matrix
The filename of the appropriate response matrix for the observation. The number after the bb (i.e., 40 in bb40) divided by 10 gives the off-axis angle of the matrix in arcmin.

File_Lcurve
Lightcurve filenames

Class
The BROWSE object classification flag.


Contact Person

Questions regarding the BBXRT database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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