Did most present-day spirals form during the last 8 Gyr? - A formation history with violent episodes revealed by panchromatic observations

By F. Hammer, H. Flores, D. Elbaz, X. Zheng, Y. Liang, C. Gepi, O. Paris, France Cea, Saclay-SAp, F. M. F. Astronomie and 4 more. 2004

195 citations recorded by the source corpus.

Studies of distant galaxies have shown that ellipticals and large spirals (Schade et al. [CITE], ApJ, 525, 31; Lilly et al. [CITE], ApJ, 500, 75) were already in place 8 Gyr ago, leading to a very modest recent star formation (Brinchmann & Ellis [CITE], ApJ, 536, L77) in intermediate mass galaxies ($3{-}30 \times 10^{10}$ $M_{\odot}$). This is challenged by a recent analysis (Heavens et al. [CITE], Nature, 428, 625) of the fossil record of the stellar populations of ~10 5 nearby galaxies, which shows that intermediate mass galaxies formed or assembled the bulk of their stars 4 to 8 Gyr ago. Here we present direct observational evidence supporting this findings from a long term, multi-wavelength study of 195 $z> 0.4$ intermediate mass galaxies, mostly selected from the Canada France Redshift Survey (CFRS). We show that recent and efficient star formation is revealed at IR wavelengths since ~15% of intermediate mass galaxies at $z> 0.4$ are indeed luminous IR galaxies (LIRGs), a phenomenon far more common than in the local Universe. The star formation in LIRGs is sufficient in itself to produce 38% of the total stellar mass of intermediate mass galaxies and then to account for most of the reported stellar mass formation since $z=1$. Observations of distant galaxies have also the potential to resolve their star formation and mass assembly histories. The high occurrence of LIRGs is easily understood only if they correspond to episodic peaks of star formation, during which galaxies are reddened through short IREs (infrared episodes). We estimate that each galaxy should experience 4 to $5 \times (\tau_{\rm IRE}/0.1~\rm Gyr)^{-1}$ IREs from $z=1$ to $z=0.4$, $\tau_{\rm IRE}$ being the characteristic timescale. An efficient and episodic star formation is further supported by the luminosity-metallicity relation of $z\sim 0.7$ emission line galaxies, which we find to be on average metal deficient by a factor of ~2 when compared to those of local spirals. We then examine how galaxy IREs can be related to the emergence at high redshift of the abundant population of galaxies with small size (but not with small mass), blue core and many irregularities. We show that recent merging and gas infall naturally explain both morphological changes and episodic star formation history in a hierarchical galaxy formation frame. We propose a simple scenario in which $75\pm25$% of intermediate mass spirals have recently experienced their last major merger event, leading to a drastic reshaping of their bulges and disks during the last 8 Gyr. It links in a simple manner distant and local galaxies, and gives account of the simultaneous decreases during that period, of the cosmic star formation density, of the merger rate, and of the number densities of LIRGs, compact and irregular galaxies, while the densities of ellipticals and large spirals are essentially unaffected. It predicts that 42, 22 and 36% of the IR (episodic) star formation density is related to major mergers, minor mergers and gas infall, respectively.

Subfields: Astronomy and Astrophysics, Computer Vision and Pattern Recognition, Instrumentation

View Paper: https://www.semanticscholar.org/paper/4a74a1eec858cbbd8deb2dd41e3c91145509e700

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Citations in the corpus

Bursting and quenching in massive galaxies without major mergers or AGNs (2007, background): “Hammer et al. (2005) have detected at least six galaxies of Md ∼ 1011 M forming stars at 120−200 M yr−1 while their morphologies and kinematics resemble spiral galaxies with no trace of major mergers.”
Semi-empirical analysis of Sloan Digital Sky Survey galaxies – II. The bimodality of the galaxy population revisited (2005, background): “The theoretical ‘downsizing’ picture still requires significant improvements, mainly concerning galaxy formation and related processes occurred since z = 1, as pointed out by Hammer et al. (2005).”
The effects of gas on morphological transformation in mergers: implications for bulge and disc demographics (2009, background): “These processes, it appears, are now being seen in a growing number of observations (Hammer et al. 2005; Trujillo & Pohlen 2005; Zheng et al. 2005; Flores et al. 2006; Puech et al. 2007a,b; Atkinson, Conselice & Fox 2007; Puech et al. 2008).”
Star Formation and the Growth of Stellar Mass (2007, background): “Given the results from ISO and Spitzer, it is now clear that massive disk galaxies host a large amount of star formation, sufficient to double their mass in a Hubble time or less (Hammer et al. 2005; Melbourne et al. 2005; Bell et al. 2005).”
MORPHOLOGICAL QUENCHING OF STAR FORMATION: MAKING EARLY-TYPE GALAXIES RED (2009, background): “…according to which the majority spiral disks would be re-built after major mergers from tidal material falling back and/or fresh infalling gas (Hammer et al. 2005), because: (1) The reformation of a star-forming disk requires a high gas infall rate (≃ 10 M⊙ yr −1) during several Gyr,…”
DUSTY INFRARED GALAXIES: Sources of the Cosmic Infrared Background (2005, methodology): “Assuming a timescale of 0.1 Gyr, Hammer et al. (2005) estimate the number of episodes per galaxies as about 5 from z = 1 to z = 0.4.”
The DEEP2 Galaxy Redshift Survey: the role of galaxy environment in the cosmic star formation history (2007, background): “…or rapid depletion of gas reservoirs or the impact on star formation of a decline in the galaxy merger rate, have been considered as possible culprits for the reduction in star–formation activity since z ∼ 1 (e.g., Le Fèvre et al. 2000; Hammer et al. 2005; Noeske et al. 2007a; Zheng et al. 2007).”
The Detailed Star Formation History in the Spheroid, Outer Disk, and Tidal Stream of the Andromeda Galaxy (2006, background): “1 (Thacker & Couchman 2001; Weil, Eke, & Efstathiou 1998), a prediction supported by panchromatic surveys of large numbers of galaxies (Hammer et al. 2005).”
The VPOS: a vast polar structure of satellite galaxies, globular clusters and streams around the Milky Way (2012, background): “As this event must have happened about 10 Gyr ago, the MW disc might have re-formed from gas accreted later (Hammer et al. 2005), with the spheroidal component being the bulge of the MW today.”
Stellar Population Diagnostics of Elliptical Galaxy Formation (2006, background): “Moreover, ∼ 50% of all stars seem to have formed at z<∼1 (Dickinson et al. 2003), and to have occurred mostly in disks (Hammer et al. 2005), whereas, if the scenario shown in Figure 6 is basically correct, then the bulk of star formation in ETGs took place at much higher redshift.”
MERGERS AND BULGE FORMATION IN ΛCDM: WHICH MERGERS MATTER? (2009, background): “…of high redshift disk+bulge systems that may represent recent re-forming or relaxing merger remnants can constrain the efficiency of bulge formation in mergers (Hammer et al. 2005; Zheng et al. 2005; Trujillo & Pohlen 2005; Flores et al. 2006; Puech et al. 2007a,b, 2008; Atkinson et al. 2007).”
The Infrared Luminosity Function of Galaxies at Redshifts z = 1 and z ~ 2 in the GOODS Fields (2007, background): “At redshift z ∼ 1, the mid-IR LF is dominated by LIRG, the majority of which are characterised by intermediate ∼ 1010 − 1011 M⊙ stellar masses (Hammer et al. 2005; Caputi et al. 2006a).”