LEDAS  
Leicester Database and Archive Service
 
ARNIE Index
ARNIE Help
ARNIE Tutorial
Search...
All databases
All helpfiles
Line
Footer
E-mail

M31STARS2: Help

M31STARS2 - MIT/Amsterdam M31 Survey


Overview

The MIT/Amsterdam M 31 Survey, or the Extended Magnier et al. Catalog of Objects in the Field of M 31, is based on deep BVRI CCD photometry that was performed on a 1 square degree region of M 31. The observations were made between September 12 and September 27 1990, using the McGraw-Hill 1.3m telescope at the Michigan-Dartmouth-MIT (MDM) observatory at Kitt Peak. The catalogue has typical completeness limits of 20.7 (Bmag), 21.7 (Vmag), 20.2 (Rmag) and 20.5 (Imag), although there is a large region in the inner disk for which the completeness limits are substantially deeper: 22.3 (Bmag), 22.2 (Vmag), 22.2 (Rmag), and 20.9 (Imag). The photometric accuracy is about 2% at Vmag = 19.

The final astrometric calibrations take into account the systematic error discovered in the Berkhuijsen et al. (1988, A&AS, 76, 65) catalog by Magnier et al. (1993, A&A, 272, 695). They are in the J2000 system and are eventually tied to the HST Guide Star Catalog. The final photometric calibrations are tied via the NGC 206 region to photometry taken at the Michigan-Dartmouth-MIT (MDM) 1.3m in September and October 1993. These are tied to the Landolt (1992, AJ, 104, 340) system of standard stars, and are in the Johnson-Kron-Cousins system (BVRcIc).


Catalog Bibcode

1992A&AS...96..379M

References

BVRI CCD photometry of 361281 objects in the field of M 31
    Magnier E.A., Lewin W.H.G., van Paradijs J., Hasinger G.,
    Jain A., Pietsch W., Truemper J.
    <Astron. Astrophys. Suppl. Ser. 96, 379 (1992)>
    =1992A&AS...96..379M
Astrometry in the field of M 31.
    Magnier E.A., Lewin W.H.G., van Paradijs J., Hasinger G.,
    Pietsch W., Truemper J.
    <Astron. Astrophys., 272, 695 (1993)>
    =1993A&A...272..695M
Extension of the Magnier et al. catalogue of objects in the field of M31.
    Haiman Z., Magnier E., Lewin W.H.G., Lester R.R., van Paradijs J.,
    Hasinger G., Pietsch W., Supper R., Truemper J.
    <Astron. Astrophys., 286, 725 (1994)>
    =1994A&A...286..725H

Provenance

This version of the MIT/Amsterdam M31 Survey Catalog was created at the HEASARC in March 1999 based on the CDS/ADC Catalogue II/208. The HEASARC revised this version in February 2001.

Caveats

There are several known problems with the catalog. First, there are likely to be some repeated detections of certain sources (i.e., multiple entries for the same object). Second, the wings of bright sources in some cases may be included as distinct sources. Third, the completeness limits are a strong function of position, and are much lower near the core and the core of M32. Fourth, variable stars, blended stars and stars with cosmic ray hits, cosmetic problems, or other failures may have highly abnormal colors and magnitudes. In general, we expect these problems to be small, but the user is cautioned to watch for these possible problems.

Naming Convention

The naming convention adopted for objects in this catalog is that suggested by the CDS Dictionary of Astronomical Nomenclature, viz. the name has been created by combining the prefix 'MLV92' (for Magnier E.A., Lewin W.H.G., van Paradijs J., et al. 1992, A&AS, 96, 379) with the sequence number given in the catalog, e.g., 'MLV92 38333'for the object with sequence number = 38333.

The HEASARC also consulted with Eugene Magnier, the first author of this catalog, in March 1999 as to his preference for the naming convention for objects in this catalog. He suggested an alternative scheme in which the prefix 'MAM31' (for MIT/Amsterdam M 31) and a kernel based on the J2000 RA and declination coordinates truncated to 0.1 seconds of time (RA) and 1 arcsecond (Dec) is used. Thus, the object with sequence number = 31 at RA(2000) = 00 hr 38 min 36.99 sec, Dec(2000) = +40 deg 03' 36.6" could be referred to as 'MAM31 J003836.9+400336', as well as 'MLV92 31'.


Parameters

Sequence_Number
A unique running number for each entry in the catalog.

Name
The catalog designation, based on the CDS recommended prefix for objects in this catalog and the sequence number. (See the section of this help on the naming convention for more details).

RA
The right ascension of the object in the default equinox. (The original equinox was J2000).

RA_Error
The scatter in the star's RA value in arcseconds, if multiple measurements were available. Notice that the average total astrometric error is estimated to be 0.8" (68% confidence).

Dec
The declination of the object in the default equinox. (The original equinox was J2000).

Dec_Error
The scatter in the star's declination value in arcseconds, if multiple measurements were available. Notice that the average total astrometric error is estimated to be 0.8" (68% confidence).

LII
The galactic longitude of the object.

BII
The galactic latitude of the object.

Bmag
The B magnitude in the Johnson photometric system.

Bmag_Error
The mean error in Bmag.

Bmag_Detects
The number of B images on which the object was detected. A negative number indicates that the object lies in a crowded area, and is likely to be either a blended image of two stars, or may be mismatched in the other filters.

Bmag_DoPHOT
The DoPHOT type number(s) for the Bmag detection(s). DoPHOT is described in Schechter et al. (1993, PASP, 105, 134). The DoPHOT type number is a number from 1 to 7 that classifies an object according to its extendedness (i.e, the extent to which its spatial profile differs from the point spread function) and the significance of the detection:

  The definitions are:
       1 = star
       2 = extended profile (i.e., galaxy)
       3 = double profile (pair of stars)
       4 = failed to converge in 4 parameter fit
       5 = large number of bad pixels (ie, near the edge of CCD)
       7 = failed to converge in 7 parameter fit.
  
This parameter contains up to 6 non-zero numbers according to the corresponding number of times that it was detected in this filter, or contains all zeroes if the star was never detected in this filter.

Vmag
The V magnitude in the Johnson photometric system.

Vmag_Error
The mean error in Vmag.

Vmag_Detects
The number of V images on which the object was detected. A negative number indicates that the object lies in a crowded area, and is likely to be either a blended image of two stars, or may be mismatched in the other filters.

Vmag_DoPHOT
The DoPHOT type number(s) for the Vmag detection(s). DoPHOT is described in Schechter et al. (1993, PASP, 105, 134). The DoPHOT type number is a number from 1 to 7 that classifies an object according to its extendedness (i.e, the extent to which its spatial profile differs from the point spread function) and the significance of the detection:

  The definitions are:
       1 = star
       2 = extended profile (i.e., galaxy)
       3 = double profile (pair of stars)
       4 = failed to converge in 4 parameter fit
       5 = large number of bad pixels (ie, near the edge of CCD)
       7 = failed to converge in 7 parameter fit.
  
This parameter contains up to 6 non-zero numbers according to the corresponding number of times that it was detected in this filter, or contains all zeroes if the star was never detected in this filter.

Rmag
The Cousins R magnitude in the Johnson/Cousins photometric system.

Rmag_Error
The mean error in Rmag.

Rmag_Detects
The number of R images on which the object was detected. A negative number indicates that the object lies in a crowded area, and is likely to be either a blended image of two stars, or may be mismatched in the other filters.

Rmag_DoPHOT
The DoPHOT type number(s) for the Rmag detection(s). DoPHOT is described in Schechter et al. (1993, PASP, 105, 134). The DoPHOT type number is a number from 1 to 7 that classifies an object according to its extendedness (i.e, the extent to which its spatial profile differs from the point spread function) and the significance of the detection:

  The definitions are:
       1 = star
       2 = extended profile (i.e., galaxy)
       3 = double profile (pair of stars)
       4 = failed to converge in 4 parameter fit
       5 = large number of bad pixels (ie, near the edge of CCD)
       7 = failed to converge in 7 parameter fit.
  
This parameter contains up to 6 non-zero numbers according to the corresponding number of times that it was detected in this filter, or contains all zeroes if the star was never detected in this filter.

Imag
The Cousins I magnitude in the Johnson/Cousins photometric system.

Imag_Error
The mean error in Imag.

Imag_Detects
The number of I images on which the object was detected. A negative number indicates that the object lies in a crowded area, and is likely to be either a blended image of two stars, or may be mismatched in the other filters.

Imag_DoPHOT
The DoPHOT type number(s) for the Imag detection(s). DoPHOT is described in Schechter et al. (1993, PASP, 105, 134). The DoPHOT type number is a number from 1 to 7 that classifies an object according to its extendedness (i.e, the extent to which its spatial profile differs from the point spread function) and the significance of the detection:

  The definitions are:
       1 = star
       2 = extended profile (i.e., galaxy)
       3 = double profile (pair of stars)
       4 = failed to converge in 4 parameter fit
       5 = large number of bad pixels (ie, near the edge of CCD)
       7 = failed to converge in 7 parameter fit.
  
This parameter contains up to 6 non-zero numbers according to the corresponding number of times that it was detected in this filter, or contains all zeroes if the star was never detected in this filter.

Class
The Browse object classification. All entries are simply classified to be stars.


Contact Person

Questions regarding the M31STARS2 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
 
HOME
SEARCH
SERVICES INFO SOFTWARE ViZieR BLASTA DSS
ARCHIVES ASCA CHANDRA GINGA ROSAT ARNIE