ELFT HÍRADÓ

[ilka AT konkoly.hu (Kalman Belane)]

                                 Meghivo
                az MTA KTM Csillagászati Kutatóintézete
                              szemináriumára

RENDKIVULI IDOPONT!

Eloado: G.M. Williger, (Univ. Kentucky)

Cim: "The Low-Redshift Lyman Alpha Forest toward PKS 0405-123"

Abstract   
We present STIS 7km/s resolution data of the Ly-a forest toward 
PKS0405-123 (z=0.574). We make two samples. The strong sample (60 systems) 
has column density logNHI>13.3 over 0.002<z<0.423, and the weak sample 
(44) has logNHI>13.1 at 0.020<z<0.234; 7 absorbers show metals, all with 
OVI, but often offset in velocity from HI. The strong sample Doppler 
parameters show <b>=47+-22km/s; for the weak, <b>=44+-21km/s. Line            
  
blending and s/n effects likely inflate b. The redshift density dN/dz is      
  
consistent with previous, lower resolution results for logNHI>14.0. For       
  
13.1<logNHI<14.0, we find a dN/dz overdensity of ~0.2-0.3 dex at              
  
0.127<z<0.234, which we believe arises from cosmic variance. We find Ly-a     
  
clustering over Delta v<250km/s for logNHI>13.3, consistent with a            
  
numerical model. There is a void in the strong sample at 0.0320<z<0.0814.     
  
We detect radial velocity correlations for Delta v<250km/s between Ly-a       
  
absorbers and 39 galaxies in a 10' field. The correlation grows with          
  
minimum NHI, peaking for logNHI ~> 13.5-14.0. The strength is similar to      
  
that of the galaxy-galaxy correlation for our sample, implying that such      
  
Ly-a systems have mass log M/Msun= 11.3+1.0-0.6. Including lower column       
  
density systems in the sample shows correlations only out to Delta v          
  
<125km/s, as would be expected for smaller density perturbations. Galaxy      
  
counts and local HI column density appear correlated, peaking at ~5000km/s.   
  
We also give column densities for Galactic species. (Abridged)                
  

A szeminárium idõpontja:  2005. november 15, kedd 11 óra

Helye: MTA Konkoly Thege Miklós Csillagászati Kutatóintézete
           1121 Budapest, Konkoly Thege Miklós út 13-17
                                                                    
                                                                    
                                     Patkós László s.k.