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

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

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

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  1. 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 FIR emission from nearby galaxiesPrinceton-Planck, Feb, 23

  2. Unique Features of Planck Mission • All-sky surveys at 100-857 GHz are unique • Supporting, nearly simultaneous, ground-based observations at frequencies below & overlapping Planck bands • A variety of time scales probed • Point sources extracted from Galactic plane (esp. cold cores)

  3. 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

  4. The ERCSC

  5. Again, compare to WMAP 7 yr. WMAP sources Planck sees Planck sources WMAP saw

  6. This talk…. Based on 5 Planck Early Papers • ERCSC paper astro-ph/1101.2041 • Statistical properties 1101.2044 • Extreme Radio Sources 1101.1721 • Blazars 1101.2047 • 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

  7. Radio Sources: Validation of Planck Results Positional accuracy of ERCSC: LFI ..and HFI In both cases < 0.2 FWHM

  8. 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

  9. 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 sources 2a. Few if any new, young GPS sources detected • Radio sources are mostly blazars 3a. And many of these are variable • Some sources have very extended, very flat spectra 4a. A challenge to jet acceleration models 5. Counts at 143 GHz fall a bit below models: relevant to ACT and SPT

  10. 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)

  11. Spectral indices show the same thing: Even at 217 --> 353 GHz, most sources have -----> synch. spectra… ….not thermal spectra ----->

  12. 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’ gallery of exceptions at 70 GHz:-- (note low galac. lat. for some) Will check out all unidentified sources at 30-70 & some at 100 & 143 GHz

  13. 2a. Few, young, GPS sources found One known young source A candidate (Planck data in red)

  14. 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

  15. 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)

  16. 4. Many have remarkably flat spectra Variability can confuse results Note expected Follow-up observations underway  = 0.5 of some blazars turn-over Solid dots () are ~simultaneous ground-based observations

  17. 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?

  18. Cosmic conspiracy -- many synch. self-absorbed components add up to a flat spectrum The basic idea… Evidence in one case, where Planck results are crucial

  19. 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?

  20. 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?

  21. No obvious connection between synch and IC peak frequencies

  22. Nearby Starforming Galaxies: Summary of Planck Findings High S/N sources at 857, 545 & 343 GHz: • Evidence for cooler dust • In some cases, two component fits required (with lower T ~ 10-20 K) one instance ---->

  23. 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 between SMGs and very local galaxies Open squares & triangles: SMGs + local galaxies . Planck Contamination by AGN synchrotron emission?

  24. Statistical properties At |b| > 5o, most 30 GHz sources are extragalactic At |b| > 5o, 100 GHZ counts may be contaminated by Galactic emission (needs to be checked)

  25. Statistical properties Based on a sample selected at 30 GHz (therefore truly extragalactic) Findings: • 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)

  26. Spectral steepening One example… These bright sources have slightly flatter spectra than AT20G sources (Murphy et al. 2010; Sajina et al. 2011)

  27. Statistics: pre-Planck 148 GHz counts

  28. Statistics: Counts (SPT, ACT & Planck) vs. models Models over-predict radio source counts by ~2

  29. (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)

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