atlasgal atlasgal apex telescope large area survey of the galaxy f. schuller, k. menten, p. schilke,...

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…)


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)


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


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


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)


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


DC-biased (MAMBO) AC-biased (SIMBA)

freq. (Hz) freq. (Hz)

Other arrays:

• APEX SZ (Berkeley ) Camera (talk by M. Pierre)

[ first light: Dec. 2005 ]



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


APEX SZ Camera: noise spectrum


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


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


- 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


- 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


- 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

atlasgal atlasgal apex telescope large area survey of the galaxy f. schuller, k. menten, p. schilke,...

Documents