Unusual and High Redshift Radio Sources Bruce Partridge, Haverford College

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Unusual (and High Redshift) Radio SourcesBruce
Partridge, Haverford College

• 1.) Ultrasteep spectrum sources (? gt 1.0)
• 2.) SCUBA sources (see also talks by Hughes)
• 3.) Young (recently activated) sources
• Gigahertz Peaked Spectrum (GPS) sources
• Compact Symmetric Objcts (CSO)
• 4.) The highest redshift the Cosmic Microwave
  Background (CMB)

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Ultrasteep Spectrum Sources

• Luminosity correlates with ?steeper spectra have
  higher L
• Emission dominated by steep-spectrum lobes.
• Hence ultrasteep sources dominate flux-limited
  samples
• So ultrasteep spectra are a useful clue to high
  redshift.
• Redshifts up to 4 (De Breuck, van Breugel et
  al., 2002)
• In some cases, highly obscured optically
  (hyper-luminous IR galaxies) some of radio
  emission from star formation?

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Gigahertz Peaked Spectrum (GPS) Sources

• High frequency spectrum synchrotron
• What causes inversion at ? lt ?p?
• Synchrotron self-absorption
• Self-absorption ? dense, compact region
• l ? ?p-1 for ?p gt10 GHz, l parsecs
• VLBA image supports.
• Why compact? Two theories
• Frustration (trapped material)
• Youth (recently activated) (small number of
  sources consistent)
• Youth more likely precursors of classical FRI
  sources, blazers?
• If young, why not variable?

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GPS Spectra and Properties
IIIZw2 note spectrum Below peak is nearly
blackbody (from Falke et al.)
GPS source from sample of Guerra et al.
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VLBA Image of an Extreme Source
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1310326

• A GPS source with ?p gt 90 GHz
• spectrum optical
  polarization spectral index

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Compact Symmetric Objects

• Classified by Phillips Mutel (1980)
• Small, double sources
• (d ,lt 1 kpc)
• Symmetrical, so separation
• ? line of sight
• Like GPS, young
• (recent work by Gugliucci,
• Taylor et al. (2005) shows
• Kinetic age 500 years)
• Are these precursors of
• FR II sources?
• If age 500 y., numbers
• dont work.

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The Cosmic Microwave Background

• T0 2.725 ? .001 K
• ? Peak at 1 mm
• Most CMB photons from
• epoch of (re)combination
• HII ? HI
• at T 3000 K (for ? 1)
• or z 1087.
• A few rescattered at z 10
• at epoch of reionization
• HI ? HII
• ? .09

COBE/FIRAS spectrum
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WMAP Image the Universe at 380,000 yrs.
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