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ATLASGALATLASGAL
APEX Telescope LargeArea Survey of
the Galaxy
F. Schuller, K. Menten, P. Schilke, et al.
Max Planck Institut für Radioastronomie
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APEX Telescope Large Areasurvey of the Galaxy
1. Survey definition
2. Instrumentation
3. Survey implementation
4. Perspectives
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ATLASGAL : Survey definition
Aims:
• Unbiased survey of massive young stars + precursors for massive protostars throughout the Galaxy
provide a consistent database for follow-up
• Derive (proto-) IMF down to 0.1 Msol in a sample of nearby regions
• Complementarity with Galactic surveys at other wavelengths (MSX, GLIMPSE, Herschel…)
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ATLASGAL : Survey definition
cf. IRAS : massive star formation is mostly in | b | < 1°…
Black: all IRAS PSC
Blue: detected at 25and 60 m
Red: satisfy Wood &Churchwell criteria(compact HII regions)
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ATLASGAL : Survey definition
IRAS(IRIS)
25 m
60 m
100 m
cf. IRAS : massive star formation is mostly in | b | < 1° but also some up to | b | = 2.5°
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… and mostly in -80° < l < +90° :
IRAS in | b | < 1°MSX in | b | < 0.5°: black=allBlue = detected at 21mRed = with F21m/F15m > 2
ATLASGAL : Survey definition
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Sensitivity: reach 1 Msol in nearby regions, and a few 10 Msol in Galactic Center
Gas mass in cores using Hildebrand (1983) andstandard physical parameters, =2, Td=50 K:
F(870 m)d = 200
pc d = 1 kpc d = 3 kpc d = 8 kpc
10 mJy 0.0033 0.083 0.75 5.3
30 mJy 0.010 0.25 2.25 16.0
50 mJy 0.017 0.42 3.75 26.5
100 mJy 0.033 0.83 7.5 53.3
ATLASGAL : Survey definition
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Shallow survey
| l | < 80° ; | b | < 2.5° to one- = 50 mJy
3- detection of 0.3 Msol at 500 pc, 11 Msol at 3 kpc
Deep survey
| l | < 80° ; | b | < 1° to one- = 10 mJy
3- detection of 0.25 Msol at 1 kpc, 16 Msol in the GC
Deeper survey
below 0.1 Msol in limited parts of nearby regions
(e.g. = 2 mJy in Rosette, 1.5 kpc)
ATLASGAL : Survey definition
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LABOCA Facility instrument:
• Large Bolometer Camera, 295 channels, 870 mAPEX beam at 870 m:
18’’= MSX pixels = Herschel at 250 m
• field of view = 10’ x 10’ large mapping speed
• pulse tube cooling down to 300 mK
• DC-coupled: total power signal, AC-biased
Instrumentation : bolometer arrays
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LABOCA instrument: AC-biased => low 1/f noise
Instrumentation : bolometer arrays
DC-biased (MAMBO) AC-biased (SIMBA)
freq. (Hz) freq. (Hz)
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Other arrays:
• APEX SZ (Berkeley ) Camera (talk by M. Pierre)
[ first light: Dec. 2005 ]
Instrumentation : bolometer arrays
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Instrumentation : bolometer arrays
APEX SZ Camera first light: 2005 Dec. 23
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Other arrays:
• APEX SZ (Berkeley ) Camera (talk by M. Pierre)
- 330 channels, 1.4 + 2 mm- DC-coupled, pulse tube cooling- Field of view = 0.4 x 0.4 deg2
=> mapping of large fractions of GP in short time
Galactic Plane = backup for average weather
870 m + 1.4 mm + 2 mm => Tdust + spectral index
Instrumentation : bolometer arrays
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APEX SZ Camera: noise spectrum
Instrumentation : bolometer arrays
raw data correlated skynoise removed
cou
nts
/ s
qrt
(Hz)
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Other arrays:
- 37 element (MPIfR) at 350 m[ late 2006 ]
- currently being designed, will probably use same technology as SIMBA :
cryostat, pairs of differentiated channels…
Small field of view => limited regions
Instrumentation : bolometer arrays
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First look survey -Main goals:
• first global view in few months• full census of most massive star forming sites, also out the Galactic midplane, up to | b | = 2.5° • demonstrate feasibility of the complete survey
- Area to observe:• | l | < 80° ; | b | < 2.5° to one- = 50 mJy+ limited regions (10° long in | b | < 1°, Orion)
to = 10 mJyTotal observing time: < 200 hours
ATLASGAL : implementation
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Full survey- Main goals:
• To have a complete census of high mass star formation in the Galaxy• To derive the protostellar IMF down to below 1 Msol in a number of nearby regions
- Proposed area to observe at 870 m:-80° < l < +80° ; | b | < 1° to = 10 mJy
+ nearby regions (e.g. Orion, Rosette, Chameleon, Lupus, R CRa) even deeper
ATLASGAL : implementation
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- Sensitivity: one- = 10 mJy• 0.4 Msol detected at 5- at 1 kpc
• 30 Msol detected at 5- in the Gal. Center- Some limited areas in a few nearby massive star forming regions down to 0.1 Msol
Total observing time: about 1000 hours
ATLASGAL : implementation
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- Fast scanning speed: e.g. 5’/s => 5 deg in 1 min., 5’ steps => 32 hoursto cover the area of the shallow survey
+ repeat with different angle = 64 hours Point source signature : 15 Hz also sensitive to extended emission
• Deep survey: Repeat several coverages with high scanning speed to reach required sensitivity
ATLASGAL : implementation
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- Follow up spectral line observations of (newly discovered) cores, to derive kinetic distances, search for infall / outflows, constrain temperatures, density structures, etc…
- extend to outer Galaxy
- combine with far-infrared (Herschel) and near-infrared (GLIMPSE) surveys
ATLASGAL : perspectives
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- This project is planned to be a long term project, to be completed in the few first years of APEX scientific operations
- This will make APEX a true Pathfinder for ALMA and Herschel !
coordination: [email protected]
ATLASGAL : conclusion