1 / 40

SUMSS: The Sydney University Molonglo Sky Survey, 1997-2005

SUMSS: The Sydney University Molonglo Sky Survey, 1997-2005. Richard Hunstead Carole Jackson Sebastian Juraszek Michael Large Tom Mauch Tara Murphy Bruce McAdam Vincent McIntyre Barbara Piestrzynska Gordon Robertson Elaine Sadler Tony Turtle George Warr. Molonglo:

garret
Télécharger la présentation

SUMSS: The Sydney University Molonglo Sky Survey, 1997-2005

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SUMSS: The Sydney University Molonglo Sky Survey, 1997-2005 E.M. Sadler

  2. Richard Hunstead Carole Jackson Sebastian Juraszek Michael Large Tom Mauch Tara Murphy Bruce McAdam Vincent McIntyre Barbara Piestrzynska Gordon Robertson Elaine Sadler Tony Turtle George Warr Molonglo: Duncan Campbell-Wilson Jeff Webb Michael White John Barry Adrian Blake Sydney: Anne Green Douglas Bock Edward Boyce Ben Chan Lawrence Cram David Crawford Ralph Davison People involved: E.M. Sadler

  3. Dedication The Sydney University Molonglo Sky Survey is dedicated to our friend and colleague Dr Michael Large, whose expertise and vision made the project possible Prototype: SKAMP (10,000 m2) operating to 1 GHz by 2007 E.M. Sadler

  4. Wide-field images of the radio sky ‘Radio Schmidt’ telescope: 2.7o field of view, excellent surface-brightness sensitivity E.M. Sadler

  5. Images of the optical & radio sky Radio 843 MHz: Mostly very distant radio galaxies (median z~1) OpticalBlue light: Mostly nearby galaxies (median z~0.1) E.M. Sadler

  6. SUMSS source populations • Predicted radio-source population at 843MHz: • Dominant population is radio galaxies (median z~1) • 10% QSOs above ~100 mJy • Increasing contribution from local starburst galaxies below ~10 mJy Jackson & Wall, 1999 E.M. Sadler

  7. Radio galaxies & black holes Radio synchrotron emission from collimated radio jets powered by an accretion disk around a supermassive black hole (Blandford & Rees 1978). E.M. Sadler

  8. A brief history of the universe… SUMSS E.M. Sadler

  9. Why the whole sky? • Radio telescopes are highly efficient machines for probing the distant universe and measuring the cosmic evolution of galaxies and their central black holes. • Developing a proper physical understanding of galaxy formation and evolution requires data sets much larger than those available in the past. “The astronomy of the 21st century will be dominated by computer-based manipulation of huge homogeneous surveys of various types of astronomical objects.’’ Van den Bergh (2000), PASP 112, 4. E.M. Sadler

  10. Processing SUMSS data Individual 2.7o diameter fields processed automatically in a data pipeline, then combined to produce final 4o x 4o mosaics with uniform sensitivity. Mosaics are catalogued using ‘decision-tree’ artificial intelligence methods to remove telescope artefacts. E.M. Sadler

  11. Automated recognition and removal of telescope artefacts Mauch, Murphy, Curran et al. (2003) E.M. Sadler

  12. Uniformity of the SUMSS catalogue E.M. Sadler

  13. SUMSS and NVSS NVSS (1400 MHz) and SUMSS (843 MHz) surveys have similar sensitivity and resolution. Overlap at declination -30o to -40o NRAO Very Large Array (VLA), New Mexico, USA E.M. Sadler

  14. SUMSS science goals What does SUMSS do (particularly) well? • Identify and study objects which are common: Cross-match with optical redshift surveys to study global properties of AGN and star-forming galaxies at z~0, local benchmark for studies of cosmic evolution (Mauch, this meeting) • Identify and study objects which are rare: e.g. High-redshift radio galaxies (Klamer, this meeting) • Identify low surface-brightness radio sources: Complete samples of giant radio galaxies, relic sources, extended sources in the Galactic Plane • Identify and monitor transient sources: (Ball, this meeting) E.M. Sadler

  15. SUMSS and optical redshift surveys Overlap with 2dF/6dF gives spectra of 10,000+ radio AGN and starburst galaxies. Local radio luminosity functions and timescales; local benchmark for high-z studies. 6dFGS spectra E.M. Sadler

  16. NVSS/SUMSS radio sources in the 6dF Galaxy Survey A census of local radio sources: • ‘Main survey’ science: • Accurate radio luminosity functions for AGN, starbursts • Clustering study via the 2-point Correlation function • Accurate z=0 benchmarks for studies of cosmic evolution • ‘Extra targets’ science: • Compact objects and some galaxies with blue colours (QSOs, starburst galaxies…) E.M. Sadler

  17. All-sky radio continuum surveys NVSS n = 1.4 GHz dec +90o to -40o • SUMSS • = 843 MHz dec -30o to -90o • Both surveys have 45” beam, 3-6 mJy det. limit, position accuracy 1-2” • <z> = 0.8 • Only 1-2% of extragalactic radio sources in local universe (z < 0.1) E.M. Sadler

  18. The 6dF Galaxy Survey (6dFGS) • Primary Survey K-selected from 2MASS-XSC (2 Micron All Sky Survey eXtended Source Catalog) • K < 12.75 • All southern sky except |b| < 10deg • 113,000 objects over 15,000deg2 • Selection from CCD photometry • Accurate K-band magnitudes! • Measures old stellar population • Dust extinction less problematic in K-band than at shorter wavelengths • 1500 fields means 75 targets per field • Spare fibres for “additional targets” E.M. Sadler

  19. Radio Source Detection • Primary Sample (K<12.75): • Preliminary list of all NVSS/SUMSS radio sources within 30” of 2MASS-XSC (~18%). • Confirmed identifications by eye • 4506 out of ~29000 observed objects in first data release accepted as genuine (~16% detection rate) • Additional Targets: • NVSS/SUMSS Radio sources within 10” of ‘extended’ objects and 5” of ‘stellar’ objects with B<18 in the SuperCOSMOS database • 6997 NVSS (dec.>-40o) and 2614 SUMSS (dec.<-50o) additional targets • 1191 NVSS (17%) and 6 SUMSS (0.2%) observed serendipitously in first data release E.M. Sadler

  20. Radio Sources in the Primary 2MASS-XSC Sample • 4506 NVSS radio sources in 6dF-DR1 • 16% Detection rate • 109 SUMSS • 7.6% Detection rate • Spectral classification for NVSS: • 1268 Aa • 162 Ae • 187 Aae • 2644 SF • 8 Star • 235 Unclassifiable (Low S/N spectra) 40% AGN , 60% SF (2dFGRS: 60% AGN , 40% SF) Largest local (z<0.1) sample of radio source redshifts ever obtained! E.M. Sadler

  21. Local radio luminosity functions 1569 AGNs -Dominate radio source population above P1.4=1023 W/Hz - AGN radio luminosity function has power-law form for 4 decades of radio power. - Unaffected by cosmic evolution(<V/Vmax>=0.51±0.01) (Mauch 2005) 2507 Star-forming galaxies - Dominate radio source population below P1.4=1023 W/Hz - All lie on radio-FIR correlation E.M. Sadler

  22. Local star-formation density • P1.4 measures star-formation rate (Sullivan et al. 2001). • Star-formation rate derived from P1.4 is free from dust extinction. • Local SF density agrees with optical and IR values. Zero point of Madau diagram (Mauch 2005) Local SF density=(0.021±0.001) Msun yr-1 Mpc-3 E.M. Sadler

  23. Fractional radio luminosity function • Many galaxies contribute to AGN luminosity function so can separate into MK bins to compute fractional LF. • Use preliminary 6dFGS K-band luminosity function (Jones et al. in prep.) AGNs • Gives probability that a galaxy of a given near-infrared magnitude is a radio source above a given radio power. • Fraction of galaxies hosting AGN increases with MK corresponding to an increase with black hole mass via MBH-Mbulge relation. (Mauch 2005) E.M. Sadler

  24. Angular clustering of radio sources (Blake et al. 2004) E.M. Sadler

  25. Real-space 2 point correlation function[Mauch & Rawlings] All SF AGN ro=7.9±0.6 Mpc 0 Mpc<s<40 Mpc ro=7.9±0.7 Mpc 0 Mpc<s<40 Mpc ro=12.6±0.9 Mpc 0 Mpc<s<40 Mpc Magliocchetti et al.(2004): ro=10.9±1.0 Mpc (AGN), ro=7.9±0.6 Mpc (ALL) Norberg et al. (2002) (2dFGRS Galaxies): bright early types: ro=13.85±1.7 Mpc faint late-type: ro=5.2±1.1 Mpc bright late-type: ro=9.0±1.4 Mpc Radio sources cluster in a similar fashion to the optical host galaxy population. E.M. Sadler

  26. SUMSS science goals What does SUMSS do (particularly) well? • Identify and study objects which are common: Cross-match with optical redshift surveys to study global properties of AGN and star-forming galaxies at z~0, local benchmark for studies of cosmic evolution (Mauch, this meeting) • Identify and study objects which are rare: e.g. High-redshift radio galaxies (Klamer, this meeting) • Identify low surface-brightness radio sources: Complete samples of giant radio galaxies, relic sources, extended sources in the Galactic Plane • Identify and monitor transient sources: (Ball, this meeting) E.M. Sadler

  27. Searching for the earliest massive galaxies in the universe (Chambers et al. 1996; De Breuck et al. 2000) (Mauch et al. 2003) Radio spectral index, a 1) Radio filter (a<-1.3, NVSS-SUMSS) 2) IR (K-band) imaging to estimate z 3) Optical/IR spectra (8m telescopes) E.M. Sadler

  28. SUMSS science goals What does SUMSS do (particularly) well? • Identify and study objects which are common: Cross-match with optical redshift surveys to study global properties of AGN and star-forming galaxies at z~0, local benchmark for studies of cosmic evolution (Mauch, this meeting) • Identify and study objects which are rare: e.g. High-redshift radio galaxies (Klamer, this meeting) • Identify low surface-brightness radio sources: Complete samples of giant radio galaxies, relic sources, extended sources in the Galactic Plane • Identify and monitor transient sources: (Ball, this meeting) E.M. Sadler

  29. Effective u-v weighting of the MOST synthesized beam Excellent uv coverage allows detection and imaging of extended, low-surface brightness radio emission E.M. Sadler

  30. A complete sample of Mpc-sized double radio galaxies from SUMSS SGRS J0331-7710: Largest-known SUMSS radio galaxy, z=0.146, projected linear size = 2.67 Mpc Giant radio galaxies (sizes > 0.7 Mpc) are believed to represent the final stages of radio galaxy evolution. SUMSS complete sample south of dec -50o, volume density is roughly one per (215 Mpc)3 Saripalli et al. 2005, AJ 130, 896 E.M. Sadler

  31. Giant radio galaxies: J0515-8100 • Projected linear size = 1.0 Mpc • Lowest-known surface brightness for a double radio galaxy • Host galaxy interacting with fainter companion; perturbations in jet axis produce the ‘fat’ radio lobes Subrahmanyan et al. 2005, ApJ in press E.M. Sadler

  32. X-ray transient XTE 1550-564 The fixed format of the Molonglo telescope makes it ideal for finding and monitoring transient and variable radio sources. Radio emission from a Galactic soft X-ray transient source Hannikainen et al. 2001 E.M. Sadler

  33. SUMSS data release policy Imaging survey of the entire southern sky now >95% complete. FITS images and catalogue are released on the web, and incorporated into international databases (NASA Skyview, NED) www.astrop.physics.usyd.edu.au/SUMSS E.M. Sadler

  34. What next? • SUMSS now >95% complete, will be finished by early 2006. • The data products (images and catalogue) are available online, have already been used in a wide range of analyses (Galactic plane, nearby galaxies, distant galaxies, large-scale structure), and will continue to be used in the future. • From 2006 the Molonglo telescope will undergo a further upgrade as a technology prototype for the Square Kilometre Array (SKAMP), allowing it to survey polarized sources and measure the redshifted 21cm line of neutral hydrogen in distant galaxies. E.M. Sadler

  35. E.M. Sadler

  36. Energy output from a black hole Energy output is set by the accretion rate onto the black hole. The Eddington limit is the maximum rate at which gas can be accreted. Above this, the luminosity is so high that radiation pressure prevents further inflow. Eddington limit is higher for more massive black holes. E.M. Sadler

  37. The AT 20GHz survey • First all-sky radio survey at mm wavelengths • Catalogue foreground discrete-source population for future CMB missions (variability, polarization particularly important). • Set up new calibration network for ATCA, ALMA at 20-100 GHz E.M. Sadler

  38. SUMSS and the AT20GHz survey AT20G detects only a small subset of low-frequency (NVSS/ SUMSS) radio sources, but almost all AT20G sources are in the SUMSS and/or NVSS catalogues - Most optical IDs are stellar (QSO candidates), many are 6dFGS ‘additional targets’ SUMSS AT20G E.M. Sadler

  39. E.M. Sadler

  40. Galaxies in the Hubble Deep Field Our deepest view of the Universe in optical light: Median redshift of z~1 implies galaxies typically appear as they were when the Universe was a third of its current age. E.M. Sadler

More Related