Transcript Document

Galaxy Evolution and Environment
Review of Radio Observations
Tiziana Venturi
[email protected]
Bologna, 5 Novembre 2009
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
Radio Loud AGNs
Radio galaxies are associated with elliptical galaxies. The radio emission is
non thermal (synchrotron) and it origins in the galaxy nucleus.
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
FRII
FRI
Symmetric
double
Wide angle tail
Radio galaxies are classified as
low power (FRI) and high power
(FRII), the divide being
P(1.4 GHz)~ 1024.5 W/Hz
The two FR classes also differ in
morphological details
Starburst Galaxies
Non thermal radio sources whose radio emission is dominated by
supernova remants and radio supernovae (P1.4GHz < 1021.5 - 22 W/Hz)
Arp 299 z=0.0103
M82 z=0.000677
NGC 253
Z=0.000811
Perez-Torres et al. 2009
HI emission in spiral galaxies
THING Survey - VLA
VIVA project (VLA)
Detailed study of HI emission possible only in the very local Universe (z<0.1)
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.)
AGN and Starbust radio emission
Environment …
Same redishift:
local environment
AGN and Starbust radio emission
… & Evolution
Different redshift:
evolution
Local Universe and role of the
environment on the radio
emission
I. Statistical properties of radio
galaxies and cluster environment
- 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?
The dense cluster environment does not seem to influence the RLF
for AGN, whose main dependance is on the optical magnitude
Field galaxies
Cluster galaxies
Auriemma et al. 1977
Ledlow & Owen 1996
Galaxies in the 6dFG sample
Mauch & Sadler 2007
But analysis on individual merging clusters seem to deviate in opposite directions:
A2255
“Universal” RLF
A3558
A3562
Comparison
sample
A3556
SC
A3558 Shapley
complex
Venturi et al. 2000
Mauduit & Mamon 2007
Miller & Owen 2003
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
Giacintucci et al. 2004
Shapley galaxies
and re-analysis of
MO03 do not show
significant
enhancement of
startburst emission
in merging custers
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
WATs and extended with radio
power close to the FRI/FRII divide
Mittal et al. 2009
Both in cooling and non cooling
clusters
Abell 2052
Core-Halo radio galaxies
Only in cooling clusters
Pcav(1042 erg/s)
Radio emission and ICM at the cluster centres know of each other
1
McNamara & Nulsen
(2007, ARAA 45, 117)
Lradio(1042 erg/s)
1
LICM(1042 erg/s)
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.
GMRT
610
MHz
Steep spectrum
emission not obviously
connected with the
central galaxy: old radio
emission?
NGC5044
HPBW 18’’ , f.c. 0.15 mJy/b
current burst
SE cold
front
HPBW 22’’
f.c. 0.7 mJy/b
GMRT 240
MHz
Same old burst? α> 1.6
Giacintucci et al 2009
Evidence of restarted activity in radio galaxies at the cluster
centres further links the radio filled cavities with the central AGN
3C317 in A2052
Steep spectrum dominated
by the diffuse emission
VLBI Active
nucleus
Venturi et al. 2004
Redshift Evolution
Statistical properties of radio AGN
and starburst galaxies
- 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
Samples of galaxies with radio
and optical information
(spectroscopic or photometric)
radio luminosity
functions in
different redshift
bins
Recent determinations of the Local Radio Luminosity Function
6dFGS D2+ NVSS
Mauch & Sadler 2007
SDSS + NVSS + FIRST
Best et al. 2005
High power & low power radio galaxies
Different evolution with cosmic time
Low Power
High Power FRI
FRI
For low power radio
galaxies in the COSMOS
field the evolution is
much weaker than at high
power (Smolcic et al. 2009)
0.1≤z≤0.35
0.35<z≤0.6
0.6<z≤0.9
0.9<z≤1.3
Strong evolution of powerful
radio sources established
long ago
Evolution of powerful radio
galaxies up to z=0.55 from
SDSS+NVSS (Donoso et al. 2009)
Dunlop & Peacock 1990
Dependance on the environment
AGNs in the SDSS
z ≤ 0.55
RLF for central radio galaxies
in the NEP sample (0.3<z<0.8)
NEP clusters
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. 2009
Local RLF
Possible evolutionary effects
for the radio loud galaxy
population (Branchesi et al.
2006)
Evolution of “passive” AGNs and star forming galaxies
zCOSMOS field (0.1<z>0.9)
Number of AGN over
control sample vs
local overdensity
AGN
Control sample
Radio
AGN
SFG
Radio-based AGN definition: Two
classes of AGN, with “passive” and
with star forming (non-passive)
galaxy host
Only “passive” AGN show
environmental dependence:
black hole masses or emission
mechanism difference?
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)
Black Hole Masses distribution
irrespective on environment ==>
difference in feeding the black hole
Triangles:High densities
Points: low densities
L1.4GHz  Cooling flow
of group/cluster
L1.4GHz  Mstar
High redshift radio galaxies and the Early Universe
Tracers of massive galaxy formation and protoclusters
Miley & De Breuck, 2008 AARev 15,67
1.4 GHz VLA over Lyα
4C41.17 at z=3.8
Powerful (P500MHz
>1027 W/Hz) steep
spectrum (α> 1)
radio galaxies at
high redshift (z>2)
Rare objects: 178
known to date
PKS1138-282 - z=2.2
X-ray over radio
MRC1182-262 proto cluster:
host galaxy surrounded by
giant Lyα halo in a 3 Mpc
scale structure of M>2x1014
MSun
Present and future radio facilities
Wide fields and the “weak” Universe
New and upgraded observational facilities over the whole radio window
ready or to be operational over the next 12-16 months
LOFAR
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
30-80 MHz
120-240 MHz
GMRT
1.4 GHz –
240 MHZ
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
GMRT
Sub-mJy to mJy sensitivity
at the LOFAR frequencies
… some examples …
Low power end of the
RLF for AGN
Starburst galaxies
locally and at high z
Very distant
radio galaxies
HI at high z
Starburst & starforming
galaxies at high z
HI dynamics in the
Local Universe
… and much more…