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11 July 20036dF workshop1 Radio sources in the 6dFGS Tom Mauch & Elaine Sadler University of Sydney ‘Main survey’ science: Faint end of radio luminosity.

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Presentation on theme: "11 July 20036dF workshop1 Radio sources in the 6dFGS Tom Mauch & Elaine Sadler University of Sydney ‘Main survey’ science: Faint end of radio luminosity."— Presentation transcript:

1 11 July 20036dF workshop1 Radio sources in the 6dFGS Tom Mauch & Elaine Sadler University of Sydney ‘Main survey’ science: Faint end of radio luminosity function for AGN, starbursts Accurate z=0 benchmarks for studies of cosmic evolution Black hole mass/velocity dispersion relation for radio AGN ‘Extra targets’ science: Compact objects and some galaxies with blue colours (QSOs, starburst galaxies…) LAST YEAR:

2 11 July 20036dF workshop2 All-sky radio continuum surveys NVSS (Condon et al. 1998) = 1.4 GHz dec +90 o to -40 o SUMSS (Bock et al. 1999; Mauch et al. 2003) = 843 MHz dec -30 o to -90 o Currently almost 85% complete ( though not catalogued), will be finished by Dec 2003 Both surveys have 45” beam, 3-6 mJy det. limit, position accuracy 1-2”

3 11 July 20036dF workshop3 Since Last Year: ~ 6% of 6dFGS galaxies in initial data release are detected as radio sources. 909 Radio sources in 14880 galaxies. 394 Additional Target spectra. All spectra eyeballed and classified. Initial database of radio detections with multiwavelength data.

4 11 July 20036dF workshop4 The Database Convenient method for searching large dataset!

5 11 July 20036dF workshop5 Radio sources in the main survey: 909 radio sources out of 14880 total objects 6% Detection Rate! Possibly because of our 10” radio optical separation cutoff. All spectra hand classified (star,Aa,Ae,Aae,SF): 399 AGN 436 Star-Forming 71 Unclassifiable 3 Stars About 50/50 split between AGN and SF in 6dFGS (60/40 in 2dFGS)

6 11 July 20036dF workshop6 Typical Spectra of Faint radio Sources in 6dFGS (1) Absorption line AGN:

7 11 July 20036dF workshop7 Typical Spectra of Faint radio Sources in 6dFGS (2) Emission Line AGN:

8 11 July 20036dF workshop8 Typical Spectra of Faint radio Sources in 6dFGS (3) Star Forming Galaxies: IRAS Source 0.28 Jy at 60  m Large fraction of SF galaxies interacting.

9 11 July 20036dF workshop9 Redshift distribution of 6dFGRS radio sources 2dF Sample 6dF Sample

10 11 July 20036dF workshop10 Radio emission from star-forming galaxies Many faint (<5mJy) NVSS sources with no IRAS detection. 6dFGS-NVSS 2dFGS-NVSS

11 11 July 20036dF workshop11 Local radio luminosity function of active and star-forming galaxies Low-luminosity AGN are hard to find Distribution of AGN radio luminosities.

12 11 July 20036dF workshop12 6dFGS ‘Additional targets’ 6dFGS unallocated fibres placed on NVSS/SUMSS radio IDs which have b J <18 mag but which are not in the main sample: 394 objects in initial data release. Stellar objects (foreground stars, QSOs, compact galaxies) Blue galaxies (starburst, AGN) What fraction of the local radio-source population is missed because hosts appear stellar? Don’t need all objects observed, just a sub-sample - i.e. flexible

13 11 July 20036dF workshop13 Detection fractions of additional targets Many additional targets are in other additional target samples, large fraction have been observed! –166 stars –61 AGN –74 Star Forming –93 Unknown About same fraction as in main survey! Possible BL-Lac population.

14 11 July 20036dF workshop14 Redshift Distribution of Additional Target Galaxies Median z=0.08 –Fainter sources –Emission line AGN –Starburst galaxies

15 11 July 20036dF workshop15 Some interesting Additional Targets (1): QSO- No previously recorded redshift. –Bright radio source (1.8 Jy in NVSS) also PKS 1955-35

16 11 July 20036dF workshop16 Some interesting Additional Targets (2): Higher-z QSO (4.9 mJy at 1.4 MHz) –Incorrect z from runz; actual z is 0.75 MgII

17 11 July 20036dF workshop17 Some interesting Additional Targets (3): Starburst Galaxy (ULIRG?) 43.5 mJy at 1.4 GHz (10 24.5 W Hz -1 ) 0.189 Jy at 60  m

18 11 July 20036dF workshop18 Some interesting Additional Targets (4): Radio emission from white dwarfs? –Willes & Wu 2003 (astro- ph/0302583) claim white dwarf pairs can be strong radio sources! –2.9 mJy radio source. –3 found in current sample. –Only 0.1 per deg 2 and 10% of these could be radio sources. –Class 2 in the initial data release, but class 4 spectrum!


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