UZH-Logo

Maintenance Infos

Constraining the low-mass end of the initial mass function with gravitational lensing


Ferreras, I; Saha, P; Leier, D; Courbin, F; Falco, E E (2010). Constraining the low-mass end of the initial mass function with gravitational lensing. Monthly Notices of the Royal Astronomical Society, 409(1):L30-L34.

Abstract

The low-mass end of the stellar initial mass function (IMF) is constrained by focusing on the baryon-dominated central regions of strong lensing galaxies. We study in this Letter the Einstein Cross (Q2237+0305), a z = 0.04 barred galaxy whose bulge acts as lens on a background quasar. The positions of the four quasar images constrain the surface mass density on the lens plane, whereas the surface brightness (H-band HST/NICMOS imaging) along with deep spectroscopy of the lens (VLT/FORS1) allows us to constrain the stellar mass content, for a range of IMFs. We find that a classical single power law (Salpeter IMF) predicts more stellar mass than the observed lensing estimates. This result is confirmed at the 99 per cent confidence level, and is robust to systematic effects due to the choice of population synthesis models, the presence of dust or the complex disc/bulge population mix. Our non-parametric methodology is more robust than kinematic estimates, as we do not need to make any assumptions about the dynamical state of the galaxy or its decomposition into bulge and disc. Over a range of low-mass power-law slopes (with Salpeter being Γ = + 1.35) we find that at a 90 per cent confidence level, slopes Γ > 0 are ruled out.

The low-mass end of the stellar initial mass function (IMF) is constrained by focusing on the baryon-dominated central regions of strong lensing galaxies. We study in this Letter the Einstein Cross (Q2237+0305), a z = 0.04 barred galaxy whose bulge acts as lens on a background quasar. The positions of the four quasar images constrain the surface mass density on the lens plane, whereas the surface brightness (H-band HST/NICMOS imaging) along with deep spectroscopy of the lens (VLT/FORS1) allows us to constrain the stellar mass content, for a range of IMFs. We find that a classical single power law (Salpeter IMF) predicts more stellar mass than the observed lensing estimates. This result is confirmed at the 99 per cent confidence level, and is robust to systematic effects due to the choice of population synthesis models, the presence of dust or the complex disc/bulge population mix. Our non-parametric methodology is more robust than kinematic estimates, as we do not need to make any assumptions about the dynamical state of the galaxy or its decomposition into bulge and disc. Over a range of low-mass power-law slopes (with Salpeter being Γ = + 1.35) we find that at a 90 per cent confidence level, slopes Γ > 0 are ruled out.

Citations

21 citations in Web of Science®
20 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

14 downloads since deposited on 02 Mar 2011
5 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:2010
Deposited On:02 Mar 2011 09:07
Last Modified:05 Apr 2016 14:33
Publisher:Wiley-Blackwell
ISSN:0035-8711
Additional Information:The definitive version is available at onlinelibrary.wiley.com
Publisher DOI:https://doi.org/10.1111/j.1745-3933.2010.00941.x
Related URLs:http://arxiv.org/abs/1008.4363
Permanent URL: https://doi.org/10.5167/uzh-41719

Download

[img]
Filetype: PDF (Verlags-PDF) - Registered users only
Size: 1MB
View at publisher
[img]
Preview
Content: Accepted Version
Filetype: PDF
Size: 302kB

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations