The University of Southampton
University of Southampton Institutional Repository

An assessment of the "too big to fail" problem for field dwarf galaxies in view of baryonic feedback effects

An assessment of the "too big to fail" problem for field dwarf galaxies in view of baryonic feedback effects
An assessment of the "too big to fail" problem for field dwarf galaxies in view of baryonic feedback effects
Recent studies have established that extreme dwarf galaxies – whether satellites or field objects – suffer from the so called “too big to fail” (TBTF) problem. Put simply, the TBTF problem consists of the fact that it is difficult to explain both the measured kinematics of dwarfs and their observed number density within the lambda cold dark matter (?CDM) framework. The most popular proposed solutions to the problem involve baryonic feedback processes. For example, reionization and baryon depletion can decrease the abundance of halos that are expected to host dwarf galaxies. Moreover, feedback related to star formation can alter the dark matter density profile in the central regions of low-mass halos. In this article we assess the TBTF problem for field dwarfs, taking explicitly into account the baryonic effects mentioned above. We find that 1) reionization feedback cannot resolve the TBTF problem on its own, because the halos in question are too massive to be affected by it; and that 2) the degree to which profile modification can be invoked as a solution to the TBTF problem depends on the radius at which galactic kinematics are measured. Based on a literature sample of ~90 dwarfs with interferometric observations in the 21 cm line of atomic hydrogen (HI), we conclude that the TBTF problem persists despite baryonic effects. However, the preceding statement assumes that the sample under consideration is representative of the general population of field dwarfs. In addition, the unexplained excess of dwarf galaxies in ?CDM could be as small as a factor of ? 1.8, given the current uncertainties in the measurement of the galactic velocity function. Both of these caveats highlight the importance of upcoming uniform surveys with HI interferometers for advancing our understanding of the issue.
0004-6361
1-13
Papastergis, E.
85052c63-65a0-4e33-9a28-2dbb2a019458
Shankar, F.
b10c91e4-85cd-4394-a18a-d4f049fd9cdb
Papastergis, E.
85052c63-65a0-4e33-9a28-2dbb2a019458
Shankar, F.
b10c91e4-85cd-4394-a18a-d4f049fd9cdb

Papastergis, E. and Shankar, F. (2016) An assessment of the "too big to fail" problem for field dwarf galaxies in view of baryonic feedback effects. Astronomy & Astrophysics, 591 (A58), 1-13. (doi:10.1051/0004-6361/201527854).

Record type: Article

Abstract

Recent studies have established that extreme dwarf galaxies – whether satellites or field objects – suffer from the so called “too big to fail” (TBTF) problem. Put simply, the TBTF problem consists of the fact that it is difficult to explain both the measured kinematics of dwarfs and their observed number density within the lambda cold dark matter (?CDM) framework. The most popular proposed solutions to the problem involve baryonic feedback processes. For example, reionization and baryon depletion can decrease the abundance of halos that are expected to host dwarf galaxies. Moreover, feedback related to star formation can alter the dark matter density profile in the central regions of low-mass halos. In this article we assess the TBTF problem for field dwarfs, taking explicitly into account the baryonic effects mentioned above. We find that 1) reionization feedback cannot resolve the TBTF problem on its own, because the halos in question are too massive to be affected by it; and that 2) the degree to which profile modification can be invoked as a solution to the TBTF problem depends on the radius at which galactic kinematics are measured. Based on a literature sample of ~90 dwarfs with interferometric observations in the 21 cm line of atomic hydrogen (HI), we conclude that the TBTF problem persists despite baryonic effects. However, the preceding statement assumes that the sample under consideration is representative of the general population of field dwarfs. In addition, the unexplained excess of dwarf galaxies in ?CDM could be as small as a factor of ? 1.8, given the current uncertainties in the measurement of the galactic velocity function. Both of these caveats highlight the importance of upcoming uniform surveys with HI interferometers for advancing our understanding of the issue.

Text
__soton.ac.uk_ude_PersonalFiles_Users_fs1y12_mydocuments_1511.08741v2.pdf - Accepted Manuscript
Download (1MB)

More information

Accepted/In Press date: 28 April 2016
e-pub ahead of print date: 13 June 2016
Published date: July 2016
Organisations: Astronomy Group

Identifiers

Local EPrints ID: 397117
URI: http://eprints.soton.ac.uk/id/eprint/397117
ISSN: 0004-6361
PURE UUID: 01122750-db3b-471d-b152-48c58119e81f

Catalogue record

Date deposited: 12 Jul 2016 15:37
Last modified: 16 Dec 2019 19:10

Export record

Altmetrics

Contributors

Author: E. Papastergis
Author: F. Shankar

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×