A Multiwavelength Study of Tadpole Galaxies in the Hubble Ultra Deep Field

Abstract

Multiwavelength data are essential in order to provide a complete picture of galaxy evolution and to inform studies of galaxies' morphological properties across cosmic time. Here we present results of a multiwavelength investigation of the morphologies of "tadpole" galaxies at intermediate redshift (0.314 < z < 3.175) in the Hubble Ultra Deep Field. These galaxies were previously selected from deep Hubble Space Telescope (HST) F775W data based on their distinct asymmetric knot-plus-tail morphologies (Straughn et al. 2006). Here we use deep Wide Field Camera 3 near-infrared imaging in addition to the HST optical data in order to study the rest-frame UV/optical morphologies of these galaxies across the redshift range 0.3<z<3.2. This study reveals that the majority of these galaxies do retain their general asymmetric morphology in the rest-frame optical over this redshift range, if not the distinct "tadpole" shape. The average stellar mass of tadpole galaxies is lower than field galaxies, with the effect being slightly greater at higher redshift within the errors. Estimated from SED fits, the average age of tadpole galaxies is younger than field galaxies in the lower redshift bin, and the average metallicity is lower (whereas the specific star formation rate for tadpoles is roughly the same as field galaxies across the redshift range probed here). These average effects combined support the conclusion that this subset of galaxies is in an active phase of assembly, either late-stage merging or cold gas accretion causing localized clumpy star-formation.

On the Spatially Resolved Star Formation History in M51. I. Hybrid UV+IR Star Formation Laws and IR Emission from Dust Heated by Old Stars

“…We transform each native point spread function (PSF) to a final PSF of our choice, using the properties of Fourier transforms of convolutions. The procedure is described in Eufrasio (2015) and Straughn et al (2015) and it is made available to the public through the Astrophysics Source Code Library.…”

OMEGA–OSIRIS mapping of emission-line galaxies in A901/2–V. The rich population of jellyfish galaxies in the multicluster system Abell 901/2

“…At first sight, the jellyfish morphology appears to resemble that of tadpole galaxies, objects first found in the higher redshift Universe probed by the Hubble Deep Field (HDF) and later studied in more detail in the Hubble Ultra Deep Field (HUDF) (Elmegreen et al 2007;Elmegreen & Elmegreen 2010;Straughn et al 2015). These are galaxies with a diffuse tail attached to a head of a bright decentralised clumpy star-forming structure (Sánchez Almeida et al 2013).…”

“…However, it is not always the case that the star formation is found to be enhanced. Some hydrodynamical simulations suggest that the quenching or enhancement could be a factor of galaxy properties, such as the inclination of the disk during the infalling on the cluster (Bekki 2014;Steinhauser et al 2016).…”

A contribution of star-forming clumps and accreting satellites to the mass assembly of z ∼ 2 galaxies

“…Despite their ubiquity at z ∼ 1-3, contradictory scenarios have been so far proposed to explain the clumps' origin and their evolution. It is not clear whether they are remnants of accreted satellites that have not been completely disrupted by galactic tides (Puech et al 2009;Puech 2010;Hopkins, Narayanan & Murray 2013;Wuyts et al 2014;Guo et al 2015;Straughn et al 2015;Ribeiro et al 2017), or if they are star-forming complexes formed in situ due to the fragmentation and local collapse of gas-rich, turbulent, highredshift discs (Elmegreen et al 2007;Bournaud et al 2008;Genzel et al 2008Genzel et al , 2011Guo et al 2012Guo et al , 2015Hinojosa-Goñi, Muñoz-Tuñón & Méndez-Abreu 2016;Mieda et al 2016;Fisher et al 2017), as predicted by simulations that find high-redshift discs to be gravitationally unstable (Noguchi 1999;Immeli et al 2004a,b;Bournaud, Elmegreen & Elmegreen 2007;Elmegreen, Bournaud & Elmegreen 2008;Bournaud, Elmegreen & Martig 2009;Dekel et al 2009;Ceverino, Dekel & Bournaud 2010;Ceverino et al 2012;Dekel & Burkert 2014;Inoue et al 2016). In particular, if clumps are formed in situ we should sometimes capture their formation, and hence detect clumps with extremely young age ( 10 Myr).…”