Extragalactic hi surveys with the feed array
Download
1 / 28

Extragalactic HI Surveys with the Feed Array - PowerPoint PPT Presentation


  • 99 Views
  • Uploaded on

Extragalactic HI Surveys with the Feed Array. Riccardo Giovanelli Cornell University. Main Scientific Goals: Investigate the faint end of the HI mass function (HIMF) Determine the local density dependence of the HIMF Map the distribution of luminous and dark matter

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 ' Extragalactic HI Surveys with the Feed Array' - kathie


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
Extragalactic hi surveys with the feed array

Extragalactic HI Surveys with the Feed Array

Riccardo Giovanelli

Cornell University


  • Main Scientific Goals:

  • Investigate the faint end of the HI mass function

  • (HIMF)

  • Determine the local density dependence of the HIMF

  • Map the distribution of luminous and dark matter

  • in the local (z < 0.1) Universe

  • Determine the gas-rich membership of nearby

  • groups of galaxies

  • Determine the population of gas-rich systems in the

  • Local Group and the periphery of the MW (HVCs)

  • Find (rare) OH Megamasers near z=0.25

  • Be surprised



Beam dilution

[by comparison, HIPASS detects 1 million solar masses at 1 Mpc in 460 sec…]



HIMF

where

Zwaan et al. 97:

Rosenberg & Schneider 02:

[Mpc**-3 dex**-1]


Source-to-beam extent

Integration time in sec

Signal width in km/s


  • The reliability of a detection depends on S/N.

  • Model the probability p, that a “detection” at given S/N

  • will be confirmed, as

  • Model W_kms as Gauss deviate with dispersion 0.1 dex about

scramble disk inclination and add turbulent term

  • Model source size as


Next,

adopt a model for the cosmic density field


Slice of the cosmic

Density field along

The Supergalactic

Plane

You are here


Where are the

Low HI mass

Systems?

Normalized Cosmic Density

  • Most of the mass is to be found in regions of density

  • substantially higher than average

Caveat:

But, do low baryonic mass systems trace the cosmic

density distribution?


  • A set of survey simulations:

  • All-AO, fast (6-sec) sky survey:

  • ALFALFA

  • 300 - sec ZOA ``staring’’ survey

  • ZOA

  • 60 - sec Virgo Cluster survey

  • VIRGO




ZOA

300 sec

|b| < 10

AO limits


ZOA

300 sec

|b| < 10

AO limits


ZOA

300 sec

|b| < 10

AO limits


Virgo

11h-13h RA

0 to 27 Dec

60 sec

800 hours





1 second

1 second





ad