Planck (and Supporting) Observations of Extragalactic “Point” Sources

Bruce Partridge, for Planck WG6

Haverford College, Haverford PA

bpartrid@haverford.edu

OUTLINE

1. Planck mission’s unique contributions

2. Radio sources: validation of ERCSC; counts and physical properties

3. FIR emission from nearby galaxies Princeton-Planck, Feb, 23

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Unique Features of Planck Mission

1. All-sky surveys at 100-857 GHz are unique

2. Supporting, nearly simultaneous, ground-based observations at frequencies below & overlapping Planck bands

3. A variety of time scales probed

4. Point sourcesextracted from Galactic plane(esp. cold cores)

Compare to WMAP

At 30-100 GHz, roughly as many sources from 10 months as WMAP in 7 years (Gold et al. 2010)

WMAP -- 471

Planck (at |b| > 5o) --

at 30 GHz -- 563

at 44 GHz -- 278

at 70 GHz -- 320

at 100 GHz ~ 800

Scores of these have supporting, approximately simultaneous ground-based measurements

The ERCSC

Again, compare to WMAP 7 yr.

WMAP sources Planck sees Planck sources WMAP saw

This talk….

Based on 5 Planck Early Papers

1. ERCSC paper astro-ph/1101.2041

2. Statistical properties 1101.2044

3. Extreme Radio Sources 1101.1721

4. Blazars 1101.2047

5. Nearby FIR galaxies 1101.2045

All source flux densities and positions from ERCSC

Conscious decision not to “skim the cream;” plenty of science left.

Open issues , further work, future plans… in italics

Radio Sources: Validation of Planck ResultsPositional accuracy of ERCSC: LFI

..and HFI

In both cases < 0.2 FWHM

Radio Sources: Validation

Flux density (possible only where catalogs or specific follow-up observations exist, e.g. 30 & 44 GHz)

Shown here: Planck-VLA comparison of unresolved sources: note close agreement of slopes

Radio Sources: Summary of Planck Findings

0. No huge surprises (unfortunately)

1. (Bright) sources at 30-143 (and generally 217) GHz are essentially all flat-spectrum radio sources (not dusty galaxies)

2. No obvious new category of extragalactic sources2a. Few if any new, young GPS sources detected3. Radio sources are mostly blazars3a. And many of these are variable4. Some sources have very extended, very flat spectra4a. A challenge to jet acceleration models5. Counts at 143 GHz fall a bit below models:

relevant to ACT and SPT

1. Sources at 30-143 (and often 217) GHz are essentially all flat-spectrum radio sources (not dusty galaxies)

The rule --------->(Planck data in red)

An exception: M82 ------->

In bright Planck sources, synchrotron dominates.(“bump” at 100 GHz may be CO)

Spectral indices show the same thing:

Even at 217 --> 353 GHz,

most sources have ----->

synch. spectra…

….not thermal spectra ----->

2. No obvious new category of extragalactic sources

>90% of Planck 30-70 GHz sources at |b| > 5o matched with cataloged radio sources with “sensible” flux densities.

Rogues’ galleryof exceptions at 70 GHz:--(note low galac.lat. for some)

Will check out all unidentifiedsources at 30-70& some at100 & 143 GHz

2a. Few, young, GPS sources found

One known young source A candidate

(Planck data in red)

3. Most ERCSC sources, even with spectral peaks, are blazars

Strongly beamed jet, general flat spectra

In some, a spectral peak:

“flaring shock-in-jet”?

(Planck LFI data in red)(Planck HFI in blue) ~simultaneous ground-based

3a. Many are variable

Detected in both long-term monitoring (U. Michigan &Metsahovi) and in Planck & simultaneous ground-based work

Effect of variability

(esp.at 44 GHz with 2

widely spaced rows

of detectors)

4. Many have remarkably flat spectra

Variability can confuse results Note expectedFollow-up observations underway = 0.5of some blazars turn-over Solid dots ( ) are ~simultaneous ground-based observations

4. Many have remarkably flat spectra

Two issues:

When 0. electron energy spectrum is N(E) E-1; rather extreme.

Or is flat spectrum a cosmic conspiracy?

Cosmic conspiracy -- many synch. self-absorbed components add up to a flat spectrum

The basic idea…

Evidence in one case,where Planck resultsare crucial

But there are many cases where the spectrum really does look like a single, smooth power law

Does this show simple Fermi acceleration (for which generally ≤ -0.6) is inadequate?

Complete SED of Blazars (plotting F)

Synchrotron peak with

synch. self-absorption

cut-off

Inverse Compton

boosted emission

at higher energy

Are peak frequencies

related?

No obvious connection between synch and IC peak frequencies

Nearby Starforming Galaxies: Summary of Planck Findings

High S/N sources at 857, 545 & 343 GHz:

1. Evidence for cooler dust

2. In some cases, two

component fits required

(with lower T ~ 10-20 K)

one instance ---->

Nearby Starforming Galaxies: Summary of Planck Findings

High S/N sources at 857, 545 & 343 GHz:

3. Planck sources fill gap in L-T plot betweenSMGs and very localgalaxies

Open squares & triangles: SMGs

+ local galaxies

. Planck

Contamination by AGN synchrotron emission?

Statistical properties

At |b| > 5o, most 30 GHz sources are extragalactic

At |b| > 5o, 100GHZ counts may be contaminated byGalacticemission (needs to be checked)

Statistical properties

Based on a sample selected at 30 GHz (therefore truly extragalactic)

Findings:1. Average spectral index

steepens above 44 or 70 GHz

2. Counts at 143 & 217 match onto ACT & SPT counts well

3. But at these frequencies, counts fall below models (probably because of #1)

Spectral steepening

• One example…

These bright sources have slightly flatter spectra than AT20G sources (Murphy et al. 2010; Sajina et al. 2011)

Statistics: pre-Planck 148 GHz counts

Statistics: Counts (SPT, ACT & Planck) vs. models

Models over-predict radio source counts by ~2

(Some) Future Work -- with 3-4, not 1.6, Surveys

Follow-up of ERCSC sources-- “unidentified” (Pearson, Chen or Partridge)-- sources with peaks in Planck frequency range (Rocha)

Investigation of resolved sources-- M31regular & anomalous dust (Clements & Dickinson)-- low-z, classic radio galaxies; spectra of lobes (Israel)

Further work on blazar SEDs (Lahteenmaki)Compiling variable sources (Rachen & Chen)Further work on flux density scales (Massardi & Partridge)Search for high-z “blobs” of sources (Montier)Initial work on polarization of sources (Caniego)Lensing enhancement of ERCSC counts around clusters

(Chary)