spica

Slide1: 

SPICA Observations of intermediate redshift galaxies Jonathan Braine Observatoire de Bordeaux

Why? (intermediate ~ 0.1 < z < 1)** Samples roughly half of all star formation** FIR emission max (rest ~ 120) within SPICA band** determine size, luminosity of objects during this period** SPICA 20 times better than PACS 60 - 205 : 

SPICA Observations of intermediate redshift galaxies Why? (intermediate ~ 0.1 < z < 1) ** Samples roughly half of all star formation ** FIR emission max (rest ~ 120) within SPICA band ** determine size, luminosity of objects during this period ** SPICA 20 times better than PACS 60 - 205 

angular size dist vs z: 

angular size dist vs z

SFR cosmique: 

SFR cosmique la formation d'étoiles dans l'univers

Spectre de NGC 4414: 

Spectre de NGC 4414

reshifted N4414: 

reshifted N4414

N4414 redshifted again: 

N4414 redshifted again

ESI line sensitivity: 

ESI line sensitivity Trust purple

ESI cont. sensitivity: 

ESI cont. sensitivity Trust purple

Sensitivity: 

Sensitivity mJy = 10^-29 W m^-2 Hz^-1 300km/s ==>  = 0.001 *  ~ 2 10^9 Hz 50 mJy = 10^-18 W m^-2 or 10^-15 erg cm^-2 sec^-1 detection of continuum emission is no problem CII to redshift z = 0.28 NII to 0.7, OI and OIII beyond z=1 Q: Are z = 0.5 galaxies brighter than todays? yes if SFR rises as universal SFR, maybe if galaxies smaller at intermediate epochs For size measurement, need vel res. of some 30km/s (R=10^4) ==> are there many small starbursting systems ? Direct size measurements not possible due to beamsize

Instrument requirements: 

Instrument requirements The goal for me is not to detect M82 at redshift x but to be able to detect M33 or the LMC. M82 while not in a starburst phase would only be slightly brighter than these local group galaxies, leading to possibly very erroneous results if we could only detect the current starbursting M82s. ==> spectral resolution of about 30km/s necessary for galaxies whose rotation curves do not reach 100 km/s OR for M51 which is close to face-on. Array size mostly pushed by local galaxies and galactic work or blind surveys.

A word about the H2 lines: 

A word about the H2 lines NGC 6946: 5 10^6 Msun (5 - 10% of total H2 in center) at 170K from ISO SWS 28 & 17 mu lines. Valentijn & vdWerf (1999) report detection of the same lines in the disk of NGC 891 and suggest a mass of some 10^10 Msun at a temperature of 80 - 90 K. If true, the warm H2 would outweigh the HI and the cool (traced by CO) H2. They note that a mechanism to suppress CII emission would be necessary. Rigopoulou et al. observed many SWS lines, detecting the S(1) 17 mu line in almost all but the S(0) 28 line in less than half. The masses of warm H2 they derive are 1 - 10% of the CO masses (cool H2) for starbursts and 1 - 35% for the AGN. A median is about 3% for these warm dense environments. They use the NGC 6946 data but not the NGC 891 result. I think the V&vdW result should not be cited without confirmation.

Other ideas: 

Other ideas Fundamental transition of HD at 112 mu: Deuterium gradient with radius in the Galaxy? Dwarf Galaxies (both tidal and low-metallicity), not just M82 !! With SPICA, we will have the sensitivity to detect many cooling lines from low-metallicity gas. Line ratios (e.g. OI 63 vs. 145) will provide a probe of the densities and temperatures of much of the ISM near the star forming regions. Are these detectable at intermediate redshifts? Outer disks of spiral local galaxies -- SF in low-metallicity low ISRF environment -- how much mass is out there? All these ideas would benefit GREATLY from R=10000 or more

Bordeaux know-how: 

Bordeaux know-how There is a sizable technical group in Bordeaux working in radioastronomy. ** HSO HIFI correlator (a Bordeaux-Toulouse collaboration) Analogical filtering of signal sent to correlator ** Bordeaux design (with Arcetri and SRON) developed in ALMA memo 476 (Quertier et al) and adopted for the new ALMA baseline correlator. Digital filtering of signal sent to correlator. While the European SPICA instrument will probably not require such filtering, future South Pole (heterodyne) instruments presumably will. Our group is interested and competent.