SCUBA-2 Surveys Galactic Surveys with SCUBA-2 Wayne Holland SCUBA-2 Project Scientist UK ATC, Royal Observatory Edinburgh

SCUBA-2 Surveys Galactic Legacy Surveys Galactic Plane survey Debris Disk survey Gould Belt survey “All-Sky” survey The JCMT Board approved 4 Galactic Legacy Surveys which will predominantly use SCUBA-2:

Galactic Plane Survey (JPS) How do massive stars form and how does their evolution influence the environment around them?

Galactic Plane Survey (JPS) Survey aims To provide the first complete samples of high-mass YSOs and protoclusters in a complete range of Galactic environments Survey logistics Awarded 330 hours of JCMT time over 2 years Coordinators: Toby Moore, Russ Shipman & René Plume

Evolution sequence for massive YSOs and reliable identifications of their evolutionary stages The variation in star formation efficiency and its relationship to triggering mechanisms and environment The origin of the stellar initial mass function and how it varies with environment Scientific Goals Galactic Plane Survey (JPS)

Scientific Goals (cont.) The nature of molecular clouds, their structure and initial conditions for star formation Investigation of cold diffuse clouds as a possible key to the nature and origin of molecular clouds The nature of the Galactic spiral structure and the global aspects of propagating star formation Galactic Plane Survey (JPS)

Survey Areas Galactic Plane Survey (JPS) Synergy with other GP surveys (GLIMPSE, UKIDSS, Herschel etc) The survey will map the regions with longitudes ranges 10° < l < 65° and 102.5° < l < 141.5° and latitude |b| ≤ 1° Total area covered will be 512 sq-degrees 8.4 GHz Galactic Plane survey by Langston et al. Orange box shows SCUBA-2 survey area for this region W49

Detection Limits Galactic Plane Survey (JPS) Survey sensitivity will be 4mJy at 850μm – a factor of ~10 lower than the SCUBA Galactic Centre dataset Corresponds to a mass sensitivity of ~1M sun at 3kpc and 40M sun at 20kpc (shown in green) Will detect all the significant high-mass and cluster- forming regions throughout the Galaxy At distances beyond 3kpc all unresolved sources detected will have masses greater than the thermal Jeans mass and are thus likely to be star-forming

Debris Disk Survey (DDS) How diverse are planetary systems and where does the Solar System fit into the picture?

Debris Disk Survey (DDS) Survey aims An unbiased search of 500 nearby main sequence stars for disk emission at 850μm Survey logistics Awarded 400 hours of JCMT time over 2 years Coordinators: Wayne Holland, Jane Greaves & Brenda Matthews

Scientific Goals Debris Disk Survey (DDS) To determine unbiased statistics on the incidence and diversity of debris disks around nearby stars τ Ceti ε Eridani Vega Fomalhaut β Pictoris Gallery of disks (to same physical scale)

Scientific Goals (cont.) Debris Disk Survey (DDS) To determine unbiased statistics on the incidence of debris disks around nearby stars To constrain disk masses and temperatures for far-IR detections (e.g. ISO, Spitzer and Herschel) Grey body fit at 55K ε Eridani (Greaves et al. 2005)

Scientific Goals (cont.) Debris Disk Survey (DDS) To discover numerous disks too cold to be detected in the far-IR To be the basis of source lists for future observing campaigns (e.g. using ALMA and JWST) To provide limits on the presence of dust that are vital to future planets detection missions (e.g. Darwin/TPF)

Survey Plan Debris Disk Survey (DDS) 500 stars comprising 100 nearest observable stars from JCMT in spectral types A, F, G, K and M All stars will be imaged at 850μm to the (extragalactic) confusion limit (~0.7 mJy) Detection rates increase sharply with lower flux limits as we probe into the mass function Disks with significant structure will be targets for further deep imaging at 450μm

Selection Criteria Debris Disk Survey (DDS) Unbiased sample for each spectral type so can distinguish between detection rates of 5,10, 25 and 50% when dataset is subdivided Stellar type with 100 stars of A, F, G, K, and M Stellar age arises naturally, with 150 stars < 1 GYr and 350 stars 1–10 Gyr Stellar multiplicity arises naturally, with one-third of stars having a companion Presence of a planetary system, with ~20 samples having one or more planets from radial velocity estimates

Gould Belt Survey (GBS) From cores to clouds: How do stars form and evolve?

Gould Belt Survey (GBS) Survey aims To provide a complete census of all pre-stellar and proto-stellar sources within 500pc of the Sun Survey logistics Awarded 370 hours of JCMT time over 2 years Coordinators: Derek Ward-Thompson, Doug Johnstone, James Di Francesco, Jennifer Hatchell & Michiel Hogerheijde

Scientific Goals To determine the relative lifetimes of the different stages of star formation - Hence the protostellar accretion rate as a function of time To determine a well-populated mass spectrum of objects over a very wide range of masses - Comparison with stellar IMF in more detail than ever before To study the structure of pre-stellar cores and investigate their formation mechanism - Possible to link the structures of cores with their environments using the same dust tracer Gould Belt Survey (GBS)

Survey Areas Most star formation within 0.5kpc lies in a region known as the Gould Belt A ring around the sky containing molecular clouds centered on a point ~200 pc from the Sun and tilted at ~20° to the Galactic Plane Gould Belt Survey (GBS)

Shallow Survey Plan Data will be sensitive to masses down to the sub-stellar limit of 0.08 M sun for objects at 0.5 kpc that have T dust = 20K, i.e. typical of the outer parts of molecular clouds (1) Map the entire GB areas (562 sq-degs) with A V > 1 at 850µm to a depth of 10mJy (2) Map 600 isolated cores (associated with GB) to the same depth including those in the Spitzer C2D programme (3) Map 10 sq-degs of blank sky split into several fields to act as a control sample Gould Belt Survey (GBS)

Deep Survey Plan (1) Map selected regions of GB cloud areas (100 sq-degs) with A V > 3 at 850µm to a depth of 3 mJy (2) Simultaneously provide maps at 450μm to a depth of 12 mJy  Create spectral index maps to constrain dust opacity and thus determine masses Data will be sensitive to masses down to the sub-stellar limit of 0.08 M sun for objects at 0.5 kpc that have T dust = 10K, i.e. typical of the inner parts of molecular clouds Gould Belt Survey (GBS)

“All-Sky” Survey (SASSy) Where do stars form in our Galaxy? Are their new populations of objects hitherto undiscovered?

“All-Sky” Survey (SASSy) Survey logistics Awarded 500 hours of JCMT time for pilot study over 2 years Coordinators: Mark Thompson, Stephen Serjeant, Tim Jenness & Douglas Scott Survey aims To produce the first high angular resolution “all-sky” atlas of the submillimetre sky visible from JCMT

Galactic Scientific Goals To act as a detection experiment and identify infrared dark clouds, star-forming cores & dusty high-redshift galaxies in as unbiased a manner as possible. Specific galactic astronomy goals include: How many infrared dark clouds (IRDCs) are there in our Galaxy and how are they distributed? What is the relation of IRDCs to star formation and Galactic structure? All-Sky Survey (SASSy)

Scientific Goals Is there an underlying unknown population of star formation? –Determine the number of dense star-forming cores over a range of galactic latitudes e.g. including known cirrus clouds What is the fraction of clustered vs isolated star formation? –Do the physical properties of isolated proto-stellar cores vary from those found in more clustered regions like Orion? What is the answer to the distributed T-Tauri problem? –By locating the earliest stages of star formation at their birthplaces can we gain insight on why weak-line T-Tauris are found far from molecular clouds? All-Sky Survey (SASSy)

SASSy Pilot Study Sensitivity will be comparable to the 850μm channel of Planck Surveyor GP-wide strip (red) covers 0 ≤ l ≤ 270° and b ≤ 5°. The pole-to-pole strip (black) is centred at l = 96° and contains the N and S galactic poles and the N ecliptic pole All-Sky Survey (SASSy)

Survey Plan SASSy is optimised to fully exploit poorer weather conditions in order to minimise the impact of such a large survey on the rest of the JCMT Legacy Survey programme SASSy will operate in the grade 4 weather band, i.e < τ (225GHz) < 0.2 By running SASSy in this weather band we also provide a fallback project at essentially all Right Ascensions for those surveys that require more demanding weather conditions All-Sky Survey (SASSy)

Spectral Line Surveys A survey of many of the cloud regions in molecular lines such as 13 CO 3-2 (330 GHz) will also be undertaken HARP-B will be used to measure the kinematics of these cores and clusters

Spectral Line Surveys Search for outflows to provide age estimates, measure line widths and velocity profiles HARP-B in fast-scan mode will achieve a 3-σ mass detection limit of 1–5 M sun per spatial point at a distance of 3 kpc (similar to SCUBA-2 but over limited fields) Outflow from Class 0 source L1157 in 12 CO 3-2

Polarisation Surveys In addition, POL-2 will make maps of the magnetic field in ten separate 1-sq-deg areas Investigate the relationship between magnetic field and cloud structure Different environments will be studied (e.g. clustered, triggered, quiescent, turbulent etc)

SCUBA-2 Surveys Galactic Legacy Surveys Galactic Plane survey Debris Disk survey Gould Belt survey “All-Sky” survey The JCMT Board approved 4 Galactic Legacy Surveys which will predominantly use SCUBA-2: The surveys are further described in the latest JCMT Newsletter: