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Review of Radio Observations Tiziana Venturi Bologna, 5 Novembre 2009 Galaxy Evolution and Environment.

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Presentation on theme: "Review of Radio Observations Tiziana Venturi Bologna, 5 Novembre 2009 Galaxy Evolution and Environment."— Presentation transcript:

1 Review of Radio Observations Tiziana Venturi Bologna, 5 Novembre 2009 Galaxy Evolution and Environment

2 Outline Radio emission in galaxies: - AGN, starburst, HI Same cosmic epoch: - Local radio luminosity function for rich and poor environments - Radio galaxies in dense environments Radio source evolution with the cosmological epoch: - Radio luminosity functions for AGNs and starbursts compared to the local RLF - Relation with the environment - Steep spectrum radio galaxies and search for protoclusters Present and future available radio facilities

3 Radio Loud AGNs Radio galaxies are associated with elliptical galaxies. The radio emission is non thermal (synchrotron) and it origins in the galaxy nucleus.

4 The radio emission takes the form of (a)symmetric jets and a central component (core) coincident with the optical nucleus. The local environment shapes the radio lobes Head Tail Wide angle tail Symmetric double Radio galaxies are classified as low power (FRI) and high power (FRII), the divide being P (1.4 GHz) ~ W/Hz The two FR classes also differ in morphological details FRII FRI

5 Starburst Galaxies Arp 299 z= M82 z= NGC 253 Z= Perez-Torres et al Non thermal radio sources whose radio emission is dominated by supernova remants and radio supernovae (P 1.4GHz < W/Hz)

6 HI emission in spiral galaxies VIVA project (VLA ) THING Survey - VLA HI emission in spirals is known to be strongly affected by the environment (field, groups, clusters, merging clusters): morphology & HI deficiency (Vollmer 2009, Virgo) Dependance of HI on cosmological epochs (up to z ~ 0.25) only recently started (Catinella et al.) Detailed study of HI emission possible only in the very local Universe (z<0.1)

7 AGN and Starbust radio emission Environment … Same redishift: local environment

8 AGN and Starbust radio emission … & Evolution Different redshift: evolution

9 Local Universe and role of the environment on the radio emission - High galaxy density in clusters compared to the field - galaxy-galaxy interaction - Large scale interaction (cluster merger) Does this affect the radio luminosity function for AGN and starburst galaxies? I. Statistical properties of radio galaxies and cluster environment

10 Auriemma et al Ledlow & Owen 1996 Field galaxies Cluster galaxies The dense cluster environment does not seem to influence the RLF for AGN, whose main dependance is on the optical magnitude But analysis on individual merging clusters seem to deviate in opposite directions: “Universal” RLF A3558 Shapley complex Venturi et al Mauduit & Mamon 2007 Comparison sample Miller & Owen 2003 Galaxies in the 6dFG sample Mauch & Sadler 2007 A2255 A3558 A3556 A3562 SC

11 Same conclusions on the radio emission from starburst galaxies Faint end of the RLF includes starbusts A2255 higher than the comparison cluster sample Miller & Owen 2003 Shapley galaxies and re-analysis of MO03 do not show significant enhancement of startburst emission in merging custers Giacintucci et al. 2004

12 Local Universe and role of the environment on the radio emission II. Radio galaxies at cluster centres: morphology, feedback and cycles of radio emission A large fraction of brightest cluster members (BCG) is radio loud (~60%) Their radio morphology can be broadly divided into two classes: Abell 400 Abell 2052 WATs and extended with radio power close to the FRI/FRII divide Both in cooling and non cooling clusters Core-Halo radio galaxies Only in cooling clusters Mittal et al. 2009

13 Radio emission and ICM at the cluster centres know of each other Feedback from the central AGN may stop the cooling - Cavities in the ICM filled by radio lobes from the central galaxies prove the role of the central AGNs. McNamara & Nulsen (2007, ARAA 45, 117) P cav (10 42 erg/s) L radio (10 42 erg/s) L ICM (10 42 erg/s) 1 1 HPBW 18’’, f.c mJy/b HPBW 22’’ f.c. 0.7 mJy/b current burst SE cold front GMRT 610 MHz GMRT 240 MHz Same old burst? α> 1.6 Giacintucci et al 2009 Steep spectrum emission not obviously connected with the central galaxy: old radio emission? NGC5044

14 3C317 in A2052 Steep spectrum dominated by the diffuse emission VLBI Active nucleus Venturi et al Evidence of restarted activity in radio galaxies at the cluster centres further links the radio filled cavities with the central AGN

15 Redshift Evolution - Evolution of the radio source population - Massive black hole formation and evolution with cosmic time - Star formation and its evolution with cosmic time - Relation with the environment Statistical properties of radio AGN and starburst galaxies Samples of galaxies with radio and optical information (spectroscopic or photometric) radio luminosity functions in different redshift bins

16 Recent determinations of the Local Radio Luminosity Function 6dFGS D2+ NVSSSDSS + NVSS + FIRST Mauch & Sadler 2007 Best et al. 2005

17 Strong evolution of powerful radio sources established long ago High power & low power radio galaxies Dunlop & Peacock 1990 Evolution of powerful radio galaxies up to z=0.55 from SDSS+NVSS (Donoso et al. 2009) 0.1≤z≤

18 Dependance on the environment AGNs in the SDSS z ≤ 0.55 Radio loud AGN are more strongly clustered than control galaxies of the same mass and quasars at the same redshif Adapted from Kauffmann et al RLF for central radio galaxies in the NEP sample (0.3

19 Evolution of “passive” AGNs and star forming galaxies zCOSMOS field ( ) Radio-based AGN definition: Two classes of AGN, with “passive” and with star forming (non-passive) galaxy host AGN SFG Only “passive” AGN show environmental dependence: black hole masses or emission mechanism difference? Number of AGN over control sample vs local overdensity Control sample Black Hole Masses distribution irrespective on environment ==> difference in feeding the black hole Radio AGN Triangles:High densities Points: low densities L 1.4GHz  M star L 1.4GHz  Cooling flow of group/cluster Only the red “passive” AGN show a density dependency In higher environments the ratio between stellar mass and emissivity is higher (signature of the cooling of the group or cluster) ==> Feedback No environmental effect on AGN hosted by star forming ==> trigger by secular (i.e. bars) phenomena (Bardelli et al. 2009)

20 High redshift radio galaxies and the Early Universe Tracers of massive galaxy formation and protoclusters Powerful (P 500MHz >10 27 W/Hz) steep spectrum (α> 1) radio galaxies at high redshift (z>2) Rare objects: 178 known to date 4C41.17 at z= GHz VLA over Lyα PKS z=2.2 X-ray over radio MRC proto cluster: host galaxy surrounded by giant Lyα halo in a 3 Mpc scale structure of M>2x10 14 M Sun Miley & De Breuck, 2008 AARev 15,67

21 Present and future radio facilities Wide fields and the “weak” Universe ALMA 10 bands from 35 to 850 GHz EVLA Complete frequency coverage from 1 to 50 GHz eVLBI and MERLIN from 1.6 to 22 GHz LOFAR MHz MHz GMRT 1.4 GHz – 240 MHZ New and upgraded observational facilities over the whole radio window ready or to be operational over the next months

22 GMRT μJy sensitivity from 1 to 50 GHz at resolutions from milliarcsecond to arcsecond scale and from ~ 20 μJy to few mJy at the ALMA frequencies Sub-mJy to mJy sensitivity at the LOFAR frequencies

23 … some examples … Low power end of the RLF for AGN Starburst galaxies locally and at high z Starburst & starforming galaxies at high z Very distant radio galaxies HI at high z HI dynamics in the Local Universe … and much more…

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