ATLASGAL ATLASGAL APEX Telescope Large Area Survey of the Galaxy F. Schuller, K. Menten, P. Schilke, et al. Max Planck Institut für Radioastronomie

APEX Telescope Large Area survey 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 M sol 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 25 and 60  m Red: satisfy Wood & Churchwell criteria (compact H II 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=all Blue = detected at 21  m Red = with F 21  m /F 15  m > 2 ATLASGAL : Survey definition

Sensitivity: reach 1 M sol in nearby regions, and a few 10 M sol in Galactic Center Gas mass in cores using Hildebrand (1983) and standard physical parameters,  =2, T d =50 K: F (870  m) d = 200 pcd = 1 kpcd = 3 kpcd = 8 kpc 10 mJy mJy mJy mJy ATLASGAL : Survey definition

Shallow survey | l | < 80° ; | b | < 2.5° to one-  = 50 mJy 3-  detection of 0.3 M sol at 500 pc, 11 M sol at 3 kpc Deep survey | l | < 80° ; | b | < 1° to one-  = 10 mJy 3-  detection of 0.25 M sol at 1 kpc, 16 M sol in the GC Deeper survey below 0.1 M sol 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  m APEX 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)

Other arrays: APEX SZ (Berkeley ) Camera (talk by M. Pierre) [ first light: Dec ] Instrumentation : bolometer arrays

APEX SZ Camera first light: 2005 Dec. 23

Other arrays: APEX SZ (Berkeley ) Camera (talk by M. Pierre) channels, mm - DC-coupled, pulse tube cooling - Field of view = 0.4 x 0.4 deg 2 => mapping of large fractions of GP in short time Galactic Plane = backup for average weather 870  m mm + 2 mm => T dust + spectral index Instrumentation : bolometer arrays

APEX SZ Camera: noise spectrum Instrumentation : bolometer arrays raw datacorrelated skynoise removed counts / sqrt(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 mJy Total 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 M sol 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 M sol detected at 5-  at 1 kpc 30 M sol detected at 5-  in the Gal. Center - Some limited areas in a few nearby massive star forming regions down to 0.1 M sol Total observing time: about 1000 hours ATLASGAL : implementation

- Fast scanning speed: e.g. 5’/s => 5 deg in 1 min., 5’ steps => 32 hours to 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: ATLASGAL : conclusion