J/A+A/493/785 Galactic disk stellar populations from ISOGAL (Ganesh+, 2009)
Stellar populations in a standard ISOGAL field in the Galactic disc.
Ganesh S., Omont A., Joshi U.C., Baliyan K.S., Schultheis M., Schuller F.,
Simon G.
<Astron. Astrophys. 493, 785 (2009)>
=2009A&A...493..785G 2009A&A...493..785G
ADC_Keywords: Infrared sources ; Stars, giant ; Photometry, infrared
Keywords: infrared: stars - Galaxy: stellar content - ISM: dust, extinction
Abstract:
We identify the stellar populations (mostly red giants and young
stars) detected in the ISOGAL survey at 7 and 15um towards a field
(LN45) in the direction l=-45, b=0.0. The sources detected in the
survey of the Galactic plane by the Infrared Space Observatory were
characterised based on colour-colour and colour-magnitude diagrams. We
combine the ISOGAL catalogue with the data from surveys such as 2MASS
and GLIMPSE. Interstellar extinction and distance were estimated using
the red clump stars detected by 2MASS in combination with the
isochrones for the AGB/RGB branch. Absolute magnitudes were thus
derived and the stellar populations identified from their absolute
magnitudes and their infrared excess. A standard approach to analysing
the ISOGAL disc observations has been established. We identify several
hundred RGB/AGB stars and 22 candidate young stellar objects in the
direction of this field in an area of 0.16deg2. An overdensity of
stellar sources is found at distances corresponding to the distance of
the Scutum-Crux spiral arm. In addition, we determined mass-loss rates
of AGB-stars using dust radiative transfer models from the literature.
Description:
Photometric parameters for 746 sources from the ISOGAL PSC1 are
presented with their corresponding measurements in the
ISOGAL/DENIS/2MASS/GLIMPSE and MSX bands. Distance, extinction and
mass-loss rates are provided for the red-giant population along with
identification of the stellar population and source reliability. This
is the complete electronic version of Table B1 of the paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 237 672 Positions, magnitudes, distance, extinction..
table2.dat 237 9 Same as table1 for flag=1 sources
(hesitation to reject)
table3.dat 237 65 Same as table1 for flag=0 sources
(rejects - single detections)
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See also:
II/243 : The ISOGAL Point Source Catalogue - IGPSC (Omont+ 2003)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
Byte-by-byte Description of file: table1.dat table2.dat table3.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Seq [1/746] Sequential number (1)
6- 13 A8 --- --- [ISOGAL-P -]
14- 29 A16 --- ISOGAL-P Standard identification
(JHHMMSS.s+DDMMSS) (2)
31- 40 F10.6 deg RAdeg Right Ascension (J2000) (3)
42- 51 F10.6 deg DEdeg Declination (J2000) (3)
53- 57 F5.2 mag Imagd ? DENIS I magnitude (4)
59- 63 F5.2 mag Jmagd ? DENIS J magnitude (4)
65- 69 F5.2 mag Kmagd ? DENIS K_s magnitude (4)
71- 74 F4.2 mag mag7 ? ISOGAL LW2 magnitude (7micron) (4)
76- 79 F4.2 mag mag15 ? ISOGAL LW3 magnitude (15micron) (4)
81- 86 F6.3 mag Jmag2 ? 2MASS J magnitude (5)
88- 93 F6.3 mag Hmag2 ? 2MASS H magnitude (5)
95-100 F6.3 mag Kmag2 ? 2MASS K magnitude (5)
102-107 F6.3 mag IRAC1 ? GLIMPSE IRAC1 3.6um magnitude (6)
109-114 F6.3 mag IRAC2 ? GLIMPSE IRAC2 4.5um magnitude (6)
116-121 F6.3 mag IRAC3 ? GLIMPSE IRAC3 5.8um magnitude (6)
123-128 F6.3 mag IRAC4 ? GLIMPSE IRAC4 8.0um magnitude (6)
130-139 E10.3 Jy B1 ? MSX B1 (4.29um) flux density (7)
141-150 E10.3 Jy B2 ? MSX B2 (4.35um) flux density (7)
152-160 E9.3 Jy A ? MSX A (8.28um) flux density (7)
162-171 E10.3 Jy C ? MSX C (12.13um) flux density (7)
173-182 E10.3 Jy D ? MSX D (14.65um) flux density (7)
184-193 E10.3 Jy E ? MSX E (21.34um) flux density (7)
195 I1 --- Flag [0/9] ISOGAL-GLIMPSE association flag (8)
197-207 A11 --- Type Stellar population type
(RG/AGB/YSOc/PNe etc)
209-215 F7.2 pc Dist ? Photometric distance
217-222 F6.3 mag AV ? Extinction in visual magnitude
225-230 F6.3 mag KMAG ? Absolute K magnitude
232-237 F6.3 [solMass/yr] logdM/dt ? Mass loss rate
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Note (1): Sequential number is the same as listed in the ISOGAL-DENIS PSC1
Note (2): Names are as listed in the ISOGAL-DENIS PSC1
Note (3): Positions are derived from the GLIMPSE positions wherever they
are not saturated. If GLIMPSE sources are saturated, we use 2MASS
positions and if 2MASS is not present, we use the ISOGAL-DENIS
astrometric position.
Note (4): Data are from ISOGAL-DENIS PSC1, Cat. II/243 (Omont et al.,
2003A&A...403..975O 2003A&A...403..975O and Schuller et al., 2003A&A...403..955S 2003A&A...403..955S).
Note (5): Data from 2MASS PSC, Cutri et al., 2003, Cat. II/246.
Note (6): Data from GLIMPSE/2MASS PSC1
http://data.spitzer.caltech.edu/popular/glimpse/20070416enhancedv2/source_lists/
Note (7): Data from MSX6C, Egan et al., 2003, Cat. V/114
Note (8): Flags as follows:
9 = Saturated in GLIMPSE IRAC4: ISOGAL (m7) brighter than 4 and no
source in GLIMPSE IRAC4
8 = Not at saturation level but no GLIMPSE - could be due to
extendedness ISOGAL (m7 & m15) present and (m7 fainter than 4
and m15 brighter than 5) and no source in GLIMPSE IRAC4
7 = Not at saturation level and GLIMPSE source in r>r0 and r<4.5"
5 = very secure associations (sep<1.5 and |m7-IRAC4|<0.3|
i.e. r<r2 and |m7-m81|<0.3 and no other GLIMPSE source within r0
4 = secure association
(1.5<sep<2.3 AND |m7-IRAC4|< 0.5) OR (sep<1.5 AND 03<|m7-IRAC4|<0.5)
4.1 = r2<r<r1 and |m7-m81|<0.5 and no other GLIMPSE source within r0
4.2 = r<r2 and 0.3<|m7-m81|<0.5 and no other GLIMPSE source within r0
4.3 = r<r2 and |m7-m81|<0.3 and m82>m7+1
(i.e. second GLIMPSE source fainter by atleast 1mag)
3 = probable association
(sep>2.3 and |m7-IRAC4|<0.5) OR
(sep<2.3 and 0.5<|m7-IRAC4|<1.2) OR
(sep<2.3 and m7>20)
3.1 = r1<r<r0 with |m7-m81|<0.5 and no other GLIMPSE source within r0
3.2 = r<r1 with 0.5<|m7-m81|<1.2 and no other GLIMPSE source
within r0
3.3 = r<r1 with m15 detection only and no other GLIMPSE source
within r0
3.4 = r<r1 for second neighbour with |m7-m82|<0.5 and |m7-m81|>0.5
- keep the second neighbour as association in this case
2 = possible association
(sep<3.8 and sep>2.3 and 0.5<|m7-IRAC4)<1.2) OR
(sep<2.3 and 1.2<|m7-IRAC4|< 2.2) OR
(sep>2.3 and m7>20)
2.1 = r1<r<r0 with 0.5<|m7-m81|<1.2 and no other GLIMPSE
2.2 = r<r1 with 1.2<|m7-m81|<2.2 and no other GLIMPSE
2.3 = r1<r<r0 with 15micron only and no other GLIMPSE within r0
2.4 = r1<r<r0 for second neighbour with |m7-m82|<1 and |m7-m81|>1.5
- keep the second neighbour as association in this case
1 = hesitation to reject
(sep<2.3 and 2.2<|m7-IRAC4|<20) OR
(2.3sep<3.8 and |m7-IRAC4|>1.2) OR
(NULL_separation and m7<20 and m15<20)
1.1 = r<r1 and |m7-m81|>2.2
1.2 = r1<r<r2 and |m7-m81|>1.2
- could be recovered with further info eg 24micron...
e.g. 7 & 15 only and no GLIMPSE within r0
or 7 with |m7-m81|>2.2 and r<r0 and no other GLIMPSE
0 = rejects - separate file
NULL_separation and (no detection at 7 or no detection at 15)
The association quality flag is defined using the parameters below:
r0 = radius of association for 10% chance of false association
r0 = 3.8 for new GLIMPSE catalogue with 4601 IRAC4 sources for LN45
r1 = 2.3"
r2 = 1.5 for LN45 field
m7 = LW2 detection
m15 = LW3 detection
m81 = nearest GLIMPSE source
m82 = next (second) nearest GLIMPSE source
The flag modification based on the GLIMPSE source quality flag:
if the SQF bit 14 is set (i.e. 8192), then degrade the ultimate
ISOGAL+GLIMPSE quality flag by 1.
* if there is also a detection at LW3 then increase the flag value by 1
* this is for sources with otherwise flags of 2 and 1 based on m7 values
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Acknowledgements:
Shashikiran Ganesh, shashikiran.ganesh(at)gmail.com
(End) S. Ganesh [IAP, France] [PRL, India], P. Vannier [CDS] 28-Jan-2009