Abstract
We show that the cosmic star formation rate per comoving volume should exhibit a distinct drop around the reionization redshift, when the H II regions in the intergalactic medium around individual ionizing sources first overlapped. The drop results from the increase in the temperature of the intergalactic medium as it was photoionized, and the consequent suppression of the formation of low-mass galaxies. We show quantitatively that the detection of this drop, which is marked by a corresponding fall in the number counts of faint galaxies, should become feasible over the coming decade with the Next Generation Space Telescope.
Highlights
Current observations reveal the existence of galaxies out to redshifts as high as z D 6.7 (Chen, Lanzetta, & Pascarelle 1999 ; Weymann et al 1998 ; Dey et al 1998 ; Spinrad et al 1998 ; Hu, Cowie, & McMahon 1998) and bright quasars out to z D 5 (Fan et al 1999)
This inference is consistent with theoretical expectations in cold dark matter (CDM) models of galaxy formation (Shapiro, Giroux, & Babul 1994 ; Gnedin & Ostriker 1997 ; Haiman & Loeb 1998, 1999a ; Valageas & Silk 1999 ; Miralda-Escude, Haehnelt, & Rees 2000 ; Chiu & Ostriker 2000 ; Gnedin 2000)
We describe the sensitivity of Next Generation Space T elescope (NGST) by spectral Ñux at wavelengths 0.6È3.5
Summary
Current observations reveal the existence of galaxies out to redshifts as high as z D 6.7 (Chen, Lanzetta, & Pascarelle 1999 ; Weymann et al 1998 ; Dey et al 1998 ; Spinrad et al 1998 ; Hu, Cowie, & McMahon 1998) and bright quasars out to z D 5 (Fan et al 1999). The detection of transmitted Ñux at rest-frame wavelengths shorter than Lya in the spectrum of some of these sources implies that most of the intergalactic medium (IGM) is ionized at z D 5 (Songaila et al 1999), and that a substantial population of ionizing sources should exist at higher redshifts (Madau, Haardt, & Rees 1999) This inference is consistent with theoretical expectations in cold dark matter (CDM) models of galaxy formation (Shapiro, Giroux, & Babul 1994 ; Gnedin & Ostriker 1997 ; Haiman & Loeb 1998, 1999a ; Valageas & Silk 1999 ; Miralda-Escude , Haehnelt, & Rees 2000 ; Chiu & Ostriker 2000 ; Gnedin 2000). Reionization is predicted to cause a drop in the cosmic star formation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
