Statistical properties of radio galaxies in the local universe
Download
1 / 12

Statistical Properties of Radio Galaxies in the local Universe - PowerPoint PPT Presentation


  • 61 Views
  • Uploaded on

Statistical Properties of Radio Galaxies in the local Universe. Yen-Ting Lin Princeton University Pontificia Universidad Católica de Chile Yue Shen, Michael Strauss, Ragnhild Lunnan (Princeton), Zheng Zheng (IAS). credit: NRAO, J. Uson. outline. motivation construction of the sample

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Statistical Properties of Radio Galaxies in the local Universe' - kapono


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Statistical properties of radio galaxies in the local universe

Statistical Properties of Radio Galaxies in the local Universe

Yen-Ting Lin

Princeton University

Pontificia Universidad Católica de Chile

Yue Shen, Michael Strauss, Ragnhild Lunnan (Princeton), Zheng Zheng (IAS)


Outline

credit: NRAO, J. Uson Universe

outline

  • motivation

  • construction of the sample

  • relationship with radio-quiet (RQ) population

  • dependence on the environment

  • formation mechanism of radio galaxies (RGs)

NGC1316 + Fornax A


Motivation sz surveys are happening

credit: CXO Universe

Carlstrom et al (2002)

motivation: SZ surveys are happening!

Atacama Cosmology Telescope in construction

see Lin et al (0805.1750) for estimation of effects of radio sources on SZ signal



The sample
the sample right

  • using NYU-VAGC DR6 LSS galaxy sample as parent sample, containing ~220,000 galaxies with measured redshifts down to Mr–20.5

  • cross-matched with NVSS and FIRST surveys at 1.4 GHz to generate the largest radio galaxy catalog to date: 10,500 RGs

  • studying luminosity function and clustering properties from volume-limited subsamples


Correlation function
correlation function right

  • both galaxies and RGs are volume-limited and subject to same optical luminosity cut (Mr–21.5)

  • RGs (red) more strongly clustered than galaxies (blue)

  • clustering length comparable to groups of galaxies (~10h-1Mpc)


Correlation function hod modeling
correlation function: HOD modeling right

  • halo occupation distribution modeling suggests RGs are hosted by halos more massive than 1013 Msun


Rgs in massive halos halo occupation number
RGs in massive halos: halo occupation number right

  • count galaxies and RGs at Mr–20.5 in 134 X-ray clusters from ROSAT all-sky survey

  • number of galaxies goes as M0.8

  • occupation number of RGs not a strong function of cluster mass

  • 1440 galaxies, 85 RGs (~6%)

  • 61/134 (=45%) clusters host RGs

  • among these, 34 have RL BCGs

  • 42 clusters host only 1 RG, 19 of these are BCG

  • 25% of BCGs are RL

  • 4% of non-BCG galaxies are RL

  • NOTE: only 1.9% of galaxies are RL globally

BCGs

clusters w/o RGs



Rgs in dense regions
RGs in dense regions right

  • excess number of neighbors

    • 1000 RGs, 1000 RQ galaxies matched to optical luminosity, apparent magnitude, and redshift

    • count nearby objects out to 2 Mpc from SDSS photometric catalog, within –23.5Mr–20.5

    • within ~0.5 Mpc, RL galaxies always have higher number of neighbors than RQ ones

Mpc


Rgs in dense regions1
RGs in dense regions right

no RLAGN–SF

galaxy pairs at

scales<1Mpc!


Conclusion
conclusion right

  • observations:

    • given optical luminosity and color, RGs are more strongly clustered than the corresponding RQ galaxy sample

    • large scale clustering implies hosts are group or cluster-sized halos

    • RGs very centrally concentrated towards halo center

  • ingredients for RL AGN phenomenon

    • dense environment

    • presence of intracluster/intragroup gas: confining pressure?

    • low level supply of gas: mass loss from old stars?

  • further tests

    • halo occupation number in optical-selected clusters

    • environment of high and low-excitation RL AGNs (e.g., FRI vs FRII)

    • matching with X-ray AGNs


ad