scholarly journals MNELLS: the MUSE nearby early-type galaxy lens locator survey

2020 ◽  
Vol 494 (1) ◽  
pp. 271-292 ◽  
Author(s):  
William P Collier ◽  
Russell J Smith ◽  
John R Lucey
Keyword(s):  
Detection Threshold ◽  
Mass Function ◽  
Initial Mass Function ◽  
Short Exposure ◽  
Early Type ◽  
Upper Limits ◽  
First Results ◽  
Robust Measurements ◽  
Blind Search ◽  
Factor Α

ABSTRACT Low-redshift strong-lensing galaxies can provide robust measurements of the stellar mass-to-light ratios in early-type galaxies (ETGs), and hence constrain variations in the stellar initial mass function (IMF). At present, only a few such systems are known. Here, we report the first results from a blind search for gravitationally lensed emission-line sources behind 52 massive z < 0.07 ETGs with Multi-Unit Spectroscopic Explorer (MUSE) integral field spectroscopy. For 16 galaxies, new observations were acquired, whilst the other 36 were analysed from archival data. This project has previously yielded one confirmed galaxy-scale strong lens (J0403−0239) that we report in an earlier paper. J0403−0239 has since received follow-up observations, presented here, which indicate support for our earlier IMF results. Three cluster-scale, and hence dark-matter-dominated, lensing systems were also discovered (central galaxies of A4059, A2052, and AS555). For nine further galaxies, we detect a singly imaged but closely projected source within 6 arcsec (including one candidate with sources at three different redshifts); such cases can be exploited to derive upper limits on the IMF mass-excess factor, α. Combining the new lens and new upper limits, with the previously discovered systems, we infer an average 〈α〉 = 1.06 ± 0.08 (marginalized over the intrinsic scatter), which is inconsistent with a Salpeter-like IMF (α = 1.55) at the 6σ level. We test the detection threshold in these short-exposure MUSE observations with the injection and recovery of simulated sources, and predict that one in 25 observations is expected to yield a new strong-lens system. Our observational results are consistent with this expected yield.

The IMF-SFH connection in massive early-type galaxies

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
I. Ferreras ◽  
C. Weidner ◽  
A. Vazdekis ◽  
F. La Barbera
Keyword(s):  
Age Distribution ◽  
Stellar Populations ◽  
Mass Function ◽  
Initial Mass Function ◽  
Population Synthesis ◽  
Early Type ◽  
Massive Galaxies ◽  
Stellar Initial Mass Function ◽  
The Many ◽  
The Imf

The stellar initial mass function (IMF) is one of the fundamental pillars in studies of stellar populations. It is the mass distribution of stars at birth, and it is traditionally assumed to be universal, adopting generic functions constrained by resolved (i.e. nearby) stellar populations (e.g., Salpeter 1955; Kroupa 2001; Chabrier 2003). However, for the vast majority of cases, stars are not resolved in galaxies. Therefore, the interpretation of the photo-spectroscopic observables is complicated by the many degeneracies present between the properties of the unresolved stellar populations, including IMF, age distribution, and chemical composition. The overall good match of the photometric and spectroscopic observations of galaxies with population synthesis models, adopting standard IMF choices, made this issue a relatively unimportant one for a number of years. However, improved models and observations have opened the door to constraints on the IMF in unresolved stellar populations via gravity-sensitive spectral features. At present, there is significant evidence of a non-universal IMF in early-type galaxies (ETGs), with a trend towards a dwarf-enriched distribution in the most massive systems (see, e.g., van Dokkum & Conroy 2010; Ferreras et al. 2013; La Barbera et al. 2013). Dynamical and strong-lensing constraints of the stellar M/L in similar systems give similar results, with heavier M/L in the most massive ETGs (see, e.g., Cappellari et al. 2012; Posacki et al. 2015). Although the interpretation of the results is still open to discussion (e.g., Smith 2014; La Barbera 2015), one should consider the consequences of such a bottom-heavy IMF in massive galaxies.

scholarly journals Origin of the prestellar core mass function and link to the IMF – Herschel first results

2010 ◽  
Vol 6 (S270) ◽  
pp. 255-262 ◽  
Author(s):  
Ph. André ◽  
A. Men'shchikov ◽  
V. Könyves ◽  
D. Arzoumanian
Keyword(s):  
Gravitational Instability ◽  
Mass Function ◽  
Initial Mass Function ◽  
Mhd Turbulence ◽  
Core Mass ◽  
Thin Filaments ◽  
Close Relationship ◽  
Prestellar Cores ◽  
First Results ◽  
The Imf

AbstractWe briefly review ground-based (sub)millimeter dust continuum observations of the prestellar core mass function (CMF) and its connection to the stellar initial mass function (IMF). We also summarize the first results obtained on this topic from the Herschel Gould Belt survey, one of the largest key projects with the Herschel Space Observatory. Our early findings with Herschel confirm the existence of a close relationship between the CMF and the IMF. Furthermore, they suggest a scenario according to which the formation of prestellar cores occurs in two main steps: 1) complex networks of long, thin filaments form first, probably as a result of interstellar MHD turbulence; 2) the densest filaments then fragment and develop prestellar cores via gravitational instability.

scholarly journals Radial variations in the stellar initial mass function of early-type galaxies

2014 ◽  
Vol 447 (2) ◽  
pp. 1033-1048 ◽  
Author(s):  
Ignacio Martín-Navarro ◽  
Francesco La Barbera ◽  
Alexandre Vazdekis ◽  
Jesús Falcón-Barroso ◽  
Ignacio Ferreras
Keyword(s):  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
Stellar Initial Mass Function

scholarly journals FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field

2020 ◽  
Vol 494 (3) ◽  
pp. 3627-3641 ◽  
Author(s):  
J R Allison ◽  
E M Sadler ◽  
S Bellstedt ◽  
L J M Davies ◽  
S P Driver ◽  
...  
Keyword(s):  
Path Length ◽  
Column Density ◽  
Radio Sources ◽  
Early Type ◽  
Absorption Path Length ◽  
Spin Temperature ◽  
Upper Limits ◽  
Blind Search ◽  
Cross Matching ◽  
Early Type Galaxy

ABSTRACT We present early science results from the First Large Absorption Survey in H i (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen (H i) gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for H i absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between z = 0.34 and 0.79 over a sky area of approximately 50 deg2. In a purely blind search, we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the H i spin temperature of Tspin = 100 K and source covering fraction cf = 1, the total comoving absorption path-length sensitive to all Damped Lyman α Absorbers (DLAs; NH i ≥ 2 × 1020 cm−2) is ΔX = 6.6 ± 0.3 (Δz = 3.7 ± 0.2) and super-DLAs (NH i ≥ 2 × 1021 cm−2) is ΔX = 111 ± 6 (Δz= 63 ± 3). We estimate upper limits on the H i column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross-matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at z = 0.3562 towards NVSS J224500−343030, with a column density of $N_{\rm H\,\small{I}} = (1.2 \pm 0.1) \times 10^{20}\, (T_{\rm spin}/100\, \mathrm{K})$ cm−2. The absorber is associated with GAMA J22450.05−343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive (MH i ≳ 3 × 109 M⊙) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.

scholarly journals EVIDENCE FOR DARK MATTER CONTRACTION AND A SALPETER INITIAL MASS FUNCTION IN A MASSIVE EARLY-TYPE GALAXY

2012 ◽  
Vol 752 (2) ◽  
pp. 163 ◽  
Author(s):  
A. Sonnenfeld ◽  
T. Treu ◽  
R. Gavazzi ◽  
P. J. Marshall ◽  
M. W. Auger ◽  
...  
Keyword(s):  
Dark Matter ◽  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
Early Type Galaxy

scholarly journals EVIDENCE FOR A CONSTANT INITIAL MASS FUNCTION IN EARLY-TYPE GALAXIES BASED ON THEIR X-RAY BINARY POPULATIONS,

2014 ◽  
Vol 784 (2) ◽  
pp. 162 ◽  
Author(s):  
Mark B. Peacock ◽  
Stephen E. Zepf ◽  
Thomas J. Maccarone ◽  
Arunav Kundu ◽  
Anthony H. Gonzalez ◽  
...  
Keyword(s):  
Mass Function ◽  
Initial Mass Function ◽  
Initial Mass ◽  
Early Type ◽  
X Ray
Sign in / Sign up

Export Citation Format

Share Document