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J/MNRAS/381/1219    High mass-loss AGB stars in the Galactic Bulge (Ojha+, 2007)
High mass-loss asymptotic giant branch stars detected by the
Midcourse Space Experiment in the "intermediate" and "outer" Galactic bulge.
    Ojha D.K., Tej A., Schultheis M., Omont A., Schuller F.
   <Mon. Not. R. Astron. Soc. 381, 1219 (2007)>
   =2007MNRAS.381.1219O
ADC_Keywords: Infrared sources ; Photometry, infrared

Keywords: stars: AGB and post-AGB - circumstellar matter - stars: mass-loss -
          dust, extinction - infrared: stars

Abstract:
    We present a study of MSX point sources in the Galactic bulge
    (|l|<3deg, 1deg<|b|<5deg), observed in the A, C, D and E bands
    (8-21um), with a total area 48 square degrees and more than 7000
    detected sources in the MSX D band (15 micron). We discuss the nature
    of the MSX sources [mostly asymptotic giant branch (AGB) stars], their
    luminosities, the interstellar extinction, the mass-loss rate
    distribution and the total mass-loss rate in the bulge. The
    mid-infrared data of MSX point sources have been combined with the
    near-infrared (J, H and Ks) data of Two Micron All Sky Survey. The
    cross-identification was restricted to Ks-band detected sources with
    Ks≤11mag. However, for those bright MSX D-band sources ([D]<4.0mag),
    which do not satisfy this criterion, we have set no Ks-band magnitude
    cut-off. The bolometric magnitudes and the corresponding luminosities
    of the MSX sources were derived by fitting blackbody curves. The
    relation between dM/dt and (Ks-[15])0 was used to derive the mass-loss
    rate of each MSX source in the bulge fields. Except for very few
    post-AGB stars, planetary nebulae and OH/IR stars, a large fraction of
    the detected sources at 15 micron (MSX D band) are AGB stars well
    above the red giant branch tip. A number of them show an excess in
    ([A]-[D])0 and (Ks-[D])0 colours, characteristic of mass-loss. These
    colours, especially (Ks-[D])0, enable estimation of the mass-loss
    rates (dM/dt) of the sources in the bulge fields which range from
    10-7 to 10-4M☉/yr. Taking into consideration the
    completeness of the mass-loss rate bins, we find that the contribution
    to the integrated mass-loss is probably dominated by mass-loss rates
    larger than 3x10-7M☉/yr and is about
    1.96x10-4M☉/yr/deg2 in the `intermediate' and `outer' bulge
    fields of sources with mass-loss rates, dM/dt>3x10-7M☉/yr. The
    corresponding integrated mass-loss rate per unit stellar mass is
    0.48x10-11/yr. Apart from this, the various mid- and near-infrared
    colour-colour and colour-magnitude diagrams are discussed in the paper
    to study the nature of the stellar population in the MSX bulge fields.

Description:
    We report the study of the MSX point sources in the 'intermediate' and
    'outer' Galactic bulge fields (|l|<3deg, 1deg<|b|<5deg) with
    a total area ∼48deg2 and more than 7000 detected sources in the MSX
    D-band (15 micron). We have combined the mid-infrared data of the MSX
    point sources with the near-infrared 2MASS data to determine their
    nature, luminosities, the interstellar extinction, the mass-loss rate
    distribution and the total mass-loss rate in the bulge.

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table1.dat        59       60   The detailed characteristics of the MSX bulge
                            subfields
table2.dat       146     2314   Catalogue of MSX-2MASS sources in the bulge fields
                            with their DENIS & ISOGAL counterparts.
table3.dat       146     1457   Sub-sample of MSX-2MASS sources from table2.dat
                            with AV, mass-loss rate & luminosity values
fig4_1.fit      2880      666   Color-magnitude diagrams (J-Ks/Ks) of 2MASS sources
                            in the bulge fields, part 1
fig4_2.fit      2880      666   Color-magnitude diagrams (J-Ks/Ks) of 2MASS sources
                            in the bulge fields, part 2
fig4_3.fit      2880      666   Color-magnitude diagrams (J-Ks/Ks) of 2MASS sources
                            in the bulge fields, part 3


See also:
          V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
         II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
         II/243 : The ISOGAL Point Source Catalogue - IGPSC (Omont+ 2003)
        B/denis : The DENIS database (DENIS Consortium, 2005)
  J/AJ/122/1844 : MSX and 2MASS cross-correlation in LMC (Egan+, 2001)
  J/A+A/405/531 : IR spec. of ISOGAL Galactic Bulge sources (Schultheis+, 2003)


Byte-by-byte Description of file: table1.dat

   Bytes Format Units   Label     Explanations

   1- 28  A28   ---     Field     MSX bulge subfields
  31- 33  I3    deg2    Dens1     MSX source density at D-band (per square deg)
  36- 39  F4.2  mag     AV        Mean interstellar extinction
  42- 45  F4.2  mag     e_AV      Sigma in interstellar extinction
  48- 50  I3    ---     N2MASS    Number of 2MASS sources (Ks≤11.0mag)
  53- 55  I3    ---     NFrgd     Number of "Foreground" sources
  58- 59  I2    ---     NB        Number of "B" sources


Byte-by-byte Description of file: table2.dat

   Bytes Format Units   Label     Explanations

   2-  6  I5    ---     Seq       Source number
   8- 13  A6    ---     ---       [MSX6C-]
  14- 30  A17   ---     MSX       MSX6C designation (GLLL.llll-bb.bbbb)
  33- 40  F8.4  deg     RAdeg     Right ascension in decimal degrees (J2000)
  43- 50  F8.4  deg     DEdeg     Declination in decimal degrees (J2000)
  54- 60  F7.4  deg     GLON      [-3/3] Galactic longitude
  64- 70  F7.4  deg     GLAT      Galactic latitude
  73- 77  F5.2  mag     Jmag      ?=99.99 2MASS J magnitude (G1)
  80- 84  F5.2  mag     Hmag      ?=99.99 2MASS H magnitude (G1)
  87- 91  F5.2  mag     Kmag      ?=99.99 2MASS Ks magnitude (G1)
  94- 98  F5.2  mag     Kmag2     ?=99.99 DENIS Ks magnitude (G1)
 101-105  F5.2  mag     Amag      ?=99.99 MSX A band (8.3um) magnitude (G1)
 108-112  F5.2  mag     Cmag      ?=99.99 MSX C band (12.1um) magnitude (G1)
 115-119  F5.2  mag     Dmag      ?=99.99 MSX D band (14.7um) magnitude (G1)
 122-126  F5.2  mag     Emag      ?=99.99 MSX E band (21.3um) magnitude (G1)
 129-133  F5.2  mag     [7]mag    ?=99.99 ISOGAL magnitude at 7 micron (G1)
 136-140  F5.2  mag     [15]mag   ?=99.99 ISOGAL magnitude at 15 micron (G1)
 142-146  F5.2  mag     AV        Interstellar extinction


Byte-by-byte Description of file: table3.dat

   Bytes Format Units     Label     Explanations

   2-  7  A6    ---       ---       [MSX6C-]
   8- 24  A17   ---       MSX       MSX6C designation (GLLL.llll-bb.bbbb)
  27- 36  A10   ---       IRAS      IRAS Name
  38- 41  F4.1  deg       GLON      [-3/3] Galactic longitude
  43- 46  F4.1  deg       GLAT      Galactic latitude
  49- 53  F5.2  mag       Jmag      ?=99.99 2MASS J magnitude (G1)
  56- 60  F5.2  mag       Hmag      ?=99.99 2MASS H magnitude (G1)
  63- 67  F5.2  mag       Kmag      2MASS Ks magnitude
  70- 74  F5.2  mag       Amag      MSX A band magnitude
  77- 81  F5.2  mag       Dmag      MSX D band magnitude
  84- 88  F5.2  mag       [7]mag    ?=99.99 ISOGAL magnitude at 7 micron (G1)
  91- 95  F5.2  mag       [15]mag   ?=99.99 ISOGAL magnitude at 15 micron (G1)
  96-101  F6.1  Jy        FC        ?=- MSX C band flux (1)
 102-107  F6.1  Jy        FE        ?=- MSX E band flux (1)
 109-113  F5.1  Jy        F12um     ?=- IRAS flux at 12 micron (1)
 115-119  F5.1  Jy        F25um     ?=- IRAS flux at 25 micron (1)
 122-125  F4.1  mag       AV        Interstellar extinction (in mag)
 129-136  E8.3  [solLum]  Lum       ?=- Luminosity
 140-146  E7.2 solMass/yr dM/dt     Mass-loss rate

Note (1): Magnitude assigned a value of "-" implies that the source is
           not detected in the corresponding band.


Global notes:

Note (G1): Magnitude assigned a value of 99.99 implies that the source is
           not detected in the corresponding band.


Acknowledgements:
    Devendra Ojha, ojha(at)tifr.res.in
(End)                                        Patricia Vannier [CDS]  03-Sep-2007