ATLASGALATLASGAL
APEX Telescope LargeArea Survey of
the Galaxy
F. Schuller, K. Menten, P. Schilke, et al.
Max Planck Institut für Radioastronomie
APEX Telescope Large Areasurvey of the Galaxy
1. Survey definition
2. Instrumentation
3. Survey implementation
4. Perspectives
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…)
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)
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°
… 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
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
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
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
LABOCA instrument: AC-biased => low 1/f noise
Instrumentation : bolometer arrays
DC-biased (MAMBO) AC-biased (SIMBA)
freq. (Hz) freq. (Hz)
Other arrays:
• APEX SZ (Berkeley ) Camera (talk by M. Pierre)
[ first light: Dec. 2005 ]
Instrumentation : bolometer arrays
Instrumentation : bolometer arrays
APEX SZ Camera first light: 2005 Dec. 23
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
APEX SZ Camera: noise spectrum
Instrumentation : bolometer arrays
raw data correlated skynoise removed
cou
nts
/ s
qrt
(Hz)
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
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
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
- 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
- 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
- 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
- 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