Bruce Partridge, Haverford College, USA (bpartrid@haverford.edu)

Outline:

- CMB studies Etudes CMB

- Radio Techniques Techniques de la radioastronomie- Radio emission from galaxies Emission radio des galaxies- Sample of contributions: Exemples de contributions:

- Star formation rate - taux de formation d’etoiles-Co-evolution of galaxies & - co-évolution de galaxies et de leurs

central Black Holes trous noirs

What Radio Astronomy Can Tell us about Galaxy Formation (and the Evolution of Cosmic Structure)

Ce que la Radioastronomie peut nous apprendre sur la Formation des Galaxies (et sur l’Evolution de la Structure

Cosmique

Studies of the Cosmic Microwave Background Radiation (Etudes du Fond Cosmique* )--the widest survey at the

earliest timeProvide values of crucial Fournit de valeurs des parametres cosmological

parameters, cosmologique important, p.ex.

Ho, DM, b, ns, wSoon to come: reionization à venir: l’histoire complete dehistory at z ~6-10 réionisation à z ~6-10

Determine amplitude of Détermine l’amplitude debaryonic density perturbations perturbations de densité baryonique at z ~ 1000 à z ~ 1000

Confirm basic linear theory Confirme la théorie linéaire de laof growth of cosmic structure croissance en densité de la structure

cosmiqueDirect link to observed Large Lieu direct avec la structure à grande scale Structure (LSS) échelle (LSS)

(Eisenstein, ApJ 633,560, 2005)

* Version française grâce å Koffi Anyinefa, Haverford College, et Jonathan Braine

CMB information is derived from measurements of (small) anisotropies in the temperature of the CMB: WMAP, ground-based work on smaller scales, and soon PlanckInformation CMB provient de mesures de (petites) anisotropies dans la température du CMB: WMAP, instruments au sol observant de plus petites échelles, et bientôt, Planck

WMAP

T/T ~ 10-5

Among the findings: b from ratio of peaks & ns from modeling the power spectrumParmi les résultats: b à partir des hauteurs des pics du spectre de puissance & ns à partir de la modelisation du spectre de puissance

Direct detection of ~1o

peak in galaxy corre-

lation function (by

Eisenstein et al.,

ApJ 663,560, 2005)

Example: New results on power spectrum on small scales Résultats nouveaux: le spectre du puissance à petite échelle

(Dunkley et al., ArXiv:109.0866)

From Atacama Cosmology Telescope (ACT)

Atacama Cosmology Telescope (ACT)

Constraints onpower spectrumof initial densityfluctuations…

..and on 8: ACT + WMAP7 give 8 = 0.82 0.04 (Sehgal et al. 2010)

SPT gives 8 = 0.75 0.02 (Lueker et al. 2009) , based on S-Z signals.

A potential surprise:CMB + He abundance imply >3 leptonfamilies (seeOct. PhysicsToday for discussionof contested high energyphysics).

Une surprise:plus de 3 espècesde lepton

Relevant (?) By-Products of CMB ResearchPlanck will produce detailed FIR & sub-mm SEDs of local galaxies

(and hence constrain dust properties, particularly cold & anomalous dust)

Planck will refine estimates of Cosmic Infrared Background

ACT & SPT can define bright end of SMG counts & luminosity function(to date,radiosources dom-inate counts)

Recent work with Anna Sajina -- extrapolating from 22 & 43 GHz observations to 148 GHz: more evidence for non-AGN contributions

to source counts below ~30 mJy

Radio Astronomical Techniques

- Very high angular resolution Très grande résolution angulaire VLBI < 10-3 arcsec

- Ability to measure gas dynamicsMesure la dynamique du gaz (using 21 cm line): see talks by (utilisant la raie a 21 cm); voir de Blok, van Gorkum….

- Gas temperature & density Température du gaz et diagnostiques

diagnostics (using, e.g., CO lines): de densité & dynamique (utilisant p.ex. see talks by Combes, Bureau … les raies CO); voir Combes, Bureau

- Redshifts of optically obscured Décalage vers le rouge z de galaxies galaxies (radio/FIR ratio & CO lines); obscurcies optiquement; voirsee Carilli &Yun, ApJ 513 L13 (1999) & talks by Françoise Combes & Martin Bureau

- ALMA will make major advances ALMA fera de grands progrès

Contributions of Continuum Radio Observations to the Understanding of Galaxy Evolution

Two general modes of radio Deux modes d’emission continuum

and submillimeter continuum radio et sub-milimetrique emission from galaxies:

1.) extended synchrotron, 1.) Rayonnement synchrotron, Brems. Bremstrahlung and dust & emission thermique de re-

emission la pousssiere, associé à la formationassociated with star formation stellaire à grand échelle

2.) AGN powered emission 2.) Rayonnement lié à l’AGN central- dominated by synchrotron - synchrotron - complex morphology - morphologie compliquée

Latter is much more luminous; No 2 est plus lumineux; donc le titrehence the title “radio galaxies” “radio galaxies”

Examples of radio emission from “ordinary” galaxies

Quiescent Star-forming

Passive

M81 M82

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Versus AGN, powered by a central Black Hole

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Ordinary (Not AGN) Galaxies in the Radio

A crucial and slightly mysterious linear correlation between FIR and radio luminosity (Helou et al., ApJ 298, L7, 1985)- Allows us to use radio as proxy for FIR emission, and thus star formation rate (SFR)(Condon, ARAA,1992)(Haarsma et al., ApJ 544, 641, 2000)

- Avoids the need to correct for dust absorption- But does require correctionfor AGN- Depends on assumption that above correlation holds independent of redshift, z- Correlation itself implies thatIMF is independent of galaxyluminosity (and therefore mass) and largely independent of z

Une correlation lineaire critique mais pas tout á fait comprise entre l’émission IR lointain (FIR) et radio

(Helou et al., ApJ 298, L7, 1985)- Nous permet d’utiliser l’ émission radio

á la place du FIR afin d’estimer le taux de formation stellaire (SFR)

- (Condon, ARAA, 1992)(Haarsma et al., ApJ 544, 641, 2000)

- Evite le besoin de corriger pour l’extinction par la poussière

- Necessite une correctionpour un eventuel noyau actif (AGN) - Dépend de l’hypothèse que cette correlation est indépendent du redshift,

z- Correlation implique que l’IMF est

indépendent de la luminosité (donc de la masse) et largement indépendent de z.

(from Ivison et al., astro-ph/1005.1072)

LIR = 10q Lrad

Note: q is independent of redshift z-- and holds for wide range of luminosity

SFR(z) fromradio dataalone (fromblind radiosurveys)

SFR(z) déterminéde radioseulement

(should be done againwith newerdata)(on doit répéteravec desobservationsrécentes) -- a

good studentproject

SFR from radio is somewhat higher than (these early) results from optical. Evidence for evolution of radio/FIR relation, or incomplete

correction for AGN, or are optical estimates too low?

Constraints on Top End of IMF

Several allusions to a possible “top-heavy” IMF at large z.Could alter radio/FIR relation:-- FIR measures total stellar energy output-- radio measures cosmic ray energy, and hence SNe (so stellar

masses 8 Mo)Need to model the effect of a changed IMF (a good student project)Complications:-- cosmic ray escape (lowers radio)-- inverse Compton energy loss on CMB (lowers radio)-- incomplete conversion of stellar light to FIR (lowers FIR)

Comment -- given the complications, remarkable that radio/FIR is so constant.

A Second Relation

Connects mass of central Black Hole to mass of halo (or better the velocity dispersion, , in km/sec ) --

MBH ~ 1.2 108 (/200)~4

Magorrian et al, 1998

Gebhardt et al. 2000

Ferrarese & Merritt 2000

Is the log-log relation linear? Are there exceptions/deviations

at the high mass end (see e.g. Lauer et al., 20007 and poster by Hlavacek-Larrondo )?

AGN and the Issue of OrientationRadio properties of

AGN depend strongly on

orientation of jet.

Hence radio properties

a poor diagnostic of

properties of central

Black Hole.

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Speculative last slide: 5 questions.

1. Heresy: Did all Early type galaxies form the same way, by mergers?

2. Heresy: Could some E galaxies form monolithically; a single, early burst of star formation? (as suggested by Eggen, Lynden-Bell & Sandage, 1962; Peebles & Partridge, 1967)

3. If so, would the relation between halo mass and central Black Hole mass be different in such galaxies?

4. Are there exceptions to the Black Hole/velocity correlation?

5. And could radio (or other) observations detect that difference?

Notice Avertissement

The Astronomical Society of the Pacific

(http://www.astrosociety.org)

On y trouve beaucoup de materiaux pour educateurs

Offers a wide range of educational material -- in English and Spanish

Would love to have some translated into French

Nous avons besoin des versions françaises

Magnetic fields

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