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J/A+A/359/347       Reddening in open and globular clusters  (Dutra+, 2000)
Foreground and background dust in star cluster directions.
       Dutra C.M., Bica E.
      <Astron. Astrophys. 359, 347 (2000)>
      =2000A&A...359..347D
ADC_Keywords: Clusters, globular ; Clusters, open ; Reddening ; Stars, distances

Keywords: Galaxy: globular clusters: general - ISM: dust, extinction -
          Galaxy: open clusters and associations: general

Abstract:
    This paper compares reddening values E(B-V) derived from the stellar
    content of 103 old open clusters and 147 globular clusters of the
    Milky Way with those derived from DIRBE/IRAS 100µm dust emission in
    the same directions. Star clusters at |b|>20° show comparable
    reddening values between the two methods, in agreement with the fact
    that most of them are located beyond the disk dust layer. For very low
    galactic latitude lines of sight, differences occur in the sense that
    DIRBE/IRAS reddening values can be substantially larger, suggesting
    effects due to the depth distribution of the dust. The differences
    appear to arise from dust in the background of the clusters consistent
    with a dust layer where important extinction occurs up to distances
    from the Plane of ≃300pc. For 3% of the sample a significant
    background dust contribution might be explained by higher dust clouds.
    We find evidence that the Milky Way dust lane and higher dust clouds
    are similar to those of several edge-on spiral galaxies recently
    studied in detail by means of CCD imaging.

Description:
    Table 2 lists the galactic globular cluster, as follows: (1) name of
    object, (2) and (3) galactic coordinates, (4) distance from the sun,
    (5) reddening derived from dust 100µm emission E(B-V)FIR, (6)
    E(B-V) derived from the light emitted by the cluster members, and (7)
    ΔE(B-V) which is the difference between E(B-V)FIR and
    E(B-V).
    Table 3 lists the galactic old open clusters, as follows: (1) name of
    object, (2 and (3) galactic coordinates, (4) distance from the sun,
    (5) age, (6) E(B-V)FIR, (7) E(B-V), and (8) ΔE(B-V). Assuming
    the Milky Way dust layer height to be |Z'|=200pc, Table 4 presents the
    60 clusters with ΔE(B-V)>0.30, showing their height from the
    Plane |Z'|, the distance in the cluster line of sight from the true
    Plane up to the dust layer edge dlayer, and the path length behind
    the cluster up to the disk border dbck. They are separated in two
    groups, one formed by clusters within the dust layer (10 globular and
    33 old open clusters) and the other by clusters outside it (15
    globular and 2 old open clusters).

File Summary:

       FileName      Lrecl  Records   Explanations

ReadMe            80        .   This file
table2.dat        72      147   Properties of Galactic globular clusters
table3.dat        61      103   Properties of Galactic old open clusters
table4.dat        33       60   Distance from the plane and lines of sight for
                                 clusters with ΔE(B-V)>0.30
tables.tex       455      403   LaTeX version of the tables


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

   Bytes Format Units   Label      Explanations

   1- 23  A23   ---     Name       Names
      25  A1    ---     n_Name     [1] Note on Names (1)
  27- 32  F6.2  deg     GLON       Galactic longitude
  34- 39  F6.2  deg     GLAT       Galacitc latitude
  41- 45  F5.1  kpc     Dsun       Distance from the sun
  47- 51  A5    ---     n_Dsun     Notes on Dsun (1)
  52- 56  F5.2  mag     E(B-V)FIR  Reddening derived from dust 100µm emission
  58- 61  F4.2  mag     E(B-V)     E(B-V) derived from the light emitted by the
                                    cluster members
  63- 66  A4    --      n_E(B-V)   Notes on E(B-V) (1)
  68- 72  F5.2  mag     DE(B-V)    Difference between E(B-V)FIR and E(B-V)

Note (1): Notes:
       1: in Sagittarius Dwarf (Ibata et al., 1994Natur.370..194I,
            Da Costa & Armandroff, 1995AJ....109.2533D)
       2: Barbuy et al. (1998A&A...333..117B)
       3: Bica et al. (1998A&AS..131..483B)
       4: Ortolani et al. (1999A&A...350..840O)
       5: Barbuy et al. (1998A&AS..132..333B)
       6: Ortolani et al. (1999A&AS..138..267O)
       7: Barbuy et al. (1999A&A...348..783B)
       8: Ortolani et al. (1999A&AS..136..237O)
       9: Kaisler et al. (1997PASP..109..920K)
      10: Rosino et al. (1997MNRAS.289..745R)
      11: Ortolani et al. (1993A&A...273..415O)
      12: Ortolani et al. (1995, Cat. J/A+A/300/726)
      13: Bica et al. (1996, Cat. J/A+AS/120/153)
      14: Ortolani et al. (1998, Cat. J/A+AS/127/471)


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

   Bytes Format Units   Label     Explanations

   1- 17  A17   ---     Name      Names
  21- 26  F6.2  deg     GLON      Galactic longitude
  28- 33  F6.2  deg     GLAT      Galacitc latitude
  35- 39  F5.2  kpc     Dsun      Distance from the sun
  41- 44  I4    Myr     t         Age
  46- 50  F5.2  mag    E(B-V)FIR  Reddening derived from dust 100µm emission
  52- 55  F4.2  mag     E(B-V)    E(B-V) derived from the light emitted by the
                                    cluster members
  57- 61  F5.2  mag     DE(B-V)   Difference between E(B-V)FIR and E(B-V)


Byte-by-byte Description of file: table4.dat

   Bytes Format Units   Label     Explanations

       1  A1    ---     Note      [wo] Cluster within (w) or outside (o)
                                        dust layer
   3- 16  A14   ---     Name      Name
      18  A1    ---     n_Name    [*] Note on line of sight (1)
  20- 23  I4    pc      |Z'|      Height from the Plane
  25- 28  F4.1  kpc     Dlayer    Distance in the cluster line of sight from the
                                   true Plane up to the dust layer edge
  30- 33  F4.1  kpc     Dbck      Path length behind the cluster up to the disk
                                   border

Note (1): *: lines of sight are truncated considering a
              galactic disk radius R=15kpc


Acknowledgements: Carlos Maxmiliano Dutra 

(End)                                        Patricia Bauer [CDS]    14-Sep-2000