A dichotomy in satellite quenching around L* galaxies

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms MNRAS 455, 4013-4029 (2016) ABSTRACTBoth theoretical predictions and observations of the very nearby Universe suggest that lowmass galaxies(log 10 [M * /M ] < 9.5) are likely to remain star-forming unless they are affected by their local environment. To test this premise, we compare and contrast the local environment of both passive and star-forming galaxies as a function of stellar mass, using the Galaxy and Mass Assembly survey. We find that passive fractions are higher in both interacting pair and group galaxies than the field at all stellar masses, and that this effect is most apparent in the lowest mass galaxies. We also find that essentially all passive log 10 [M * /M ] < 8.5 galaxies are found in pair/group environments, suggesting that local interactions with a more massive neighbour cause them to cease forming new stars. We find that the effects of immediate environment (local galaxy-galaxy interactions) in forming passive systems increase with decreasing stellar mass, and highlight that this is potentially due to increasing interaction time-scales giving sufficient time for the galaxy to become passive via starvation. We then present a simplistic model to test this premise, and show that given our speculative assumptions, it is consistent with our observed results.

Section: Pa S S I V E F R Ac T I O N S O F G a L A X I E S A S A F U contrasting

confidence: 40%

Section: Introductionmentioning

confidence: 89%

See 1 more Smart Citation

Galaxy And Mass Assembly (GAMA): growing up in a bad neighbourhood – how do low-mass galaxies become passive?

Davies

Robotham

Driver

et al. 2015

“…While the stel-lar mass or surface mass density of a galaxy may be more closely connected to quenching for massive systems (Peng et al 2010;Cheung et al 2012;Woo et al 2013), recent work has shown that environment is likely the dominant driver of quenching at the lowest mass scales (M < 10 9 M , Geha et al 2012). For example, studies comparing satellite galaxies to isolated field systems of similar stellar mass in the local Universe find that satellites tend to exhibit lower star formation rates, more bulge-dominated morphologies, as well as older and more metal-rich stellar populations (Baldry et al 2006;van den Bosch et al 2008;Cooper et al 2010b;Pasquali et al 2010;Tollerud et al 2011;Phillips et al 2014). This observed suppression of star formation in satellite galaxies is commonly referred to as "environmental quenching".…”

Section: Introductionmentioning

confidence: 99%

Taking care of business in a flash : constraining the time-scale for low-mass satellite quenching with ELVIS

Fillingham

Cooper

Wheeler

et al. 2015

Self Cite

139

190

The vast majority of dwarf satellites orbiting the Milky Way and M31 are quenched, while comparable galaxies in the field are gas-rich and star-forming. Assuming that this dichotomy is driven by environmental quenching, we use the ELVIS suite of N -body simulations to constrain the characteristic timescale upon which satellites must quench following infall into the virial volumes of their hosts. The high satellite quenched fraction observed in the Local Group demands an extremely short quenching timescale (∼ 2 Gyr) for dwarf satellites in the mass range M ∼ 10 6 − 10 8 M . This quenching timescale is significantly shorter than that required to explain the quenched fraction of more massive satellites (∼ 8 Gyr), both in the Local Group and in more massive host halos, suggesting a dramatic change in the dominant satellite quenching mechanism at M 10 8 M . Combining our work with the results of complementary analyses in the literature, we conclude that the suppression of star formation in massive satellites (M ∼ 10 8 − 10 11 M ) is broadly consistent with being driven by starvation, such that the satellite quenching timescale corresponds to the cold gas depletion time. Below a critical stellar mass scale of ∼ 10 8 M , however, the required quenching times are much shorter than the expected cold gas depletion times. Instead, quenching must act on a timescale comparable to the dynamical time of the host halo. We posit that ram-pressure stripping can naturally explain this behavior, with the critical mass (of M ∼ 10 8 M ) corresponding to halos with gravitational restoring forces that are too weak to overcome the drag force encountered when moving through an extended, hot circumgalactic medium.

“…However, the environmental quenching of dwarfs is far from ubiquitous (e.g. Phillips et al 2014Phillips et al , 2015Wheeler et al 2014). …”

Section: Introductionmentioning

confidence: 99%

Deep spectroscopy of nearby galaxy clusters – I. Spectroscopic luminosity function of Abell 85

Agulli¹,

Aguerri²,

Sánchéz-Janssen³

et al. 2016

We present a new deep spectroscopic catalogue for Abell 85, within 3.0 × 2.6 Mpc 2 and down to M r ∼ M * r +6. Using the Visible Multi-Object Spectrograph at the Very Large Telescope and the AutoFiber 2 at the William Herschel Telescope, we obtained almost 1430 new redshifts for galaxies with m r ≤ 21 mag and µ e,r ≤ 24 mag arcsec −2 . These redshifts, together with SDSS-DR6 and NED spectroscopic information, result in 460 confirmed cluster members. This data set allows the study of the luminosity function (LF) of the cluster galaxies covering three orders of magnitudes in luminosities. The total and radial LFs are best modelled by a double Schechter function. The normalized LFs show that their bright (M r ≤ −21.5) and faint (M r ≥ −18.0) ends are independent of clustercentric distance and similar to the field LFs unlike the intermediate luminosity range (−21.5 ≤ M r ≤ −18.0). Similar results are found for the LFs of the dominant types of galaxies: red, passive, virialized and early-infall members. On the contrary, the LFs of blue, star-forming, non-virialized and recent-infall galaxies are well described by a single Schechter function. These populations contribute to a small fraction of the galaxy density in the innermost cluster region. However, in the outskirts of the cluster, they have similar densities to red, passive, virialized and early-infall members at the LF faint end. These results confirm a clear dependence of the colour and star formation of Abell 85 members in the cluster centric distance.