scholarly journals Robust H i kinematics of gas-rich ultra-diffuse galaxies: hints of a weak-feedback formation scenario

2020 ◽  
Vol 495 (4) ◽  
pp. 3636-3655 ◽  
Author(s):  
Pavel E Mancera Piña ◽  
Filippo Fraternali ◽  
Kyle A Oman ◽  
Elizabeth A K Adams ◽  
Cecilia Bacchini ◽  
...  
Keyword(s):  
Formation Rate ◽  
Rotation Velocity ◽  
Gas Kinematics ◽  
Stellar Feedback ◽  
Low Surface Brightness ◽  
Kinematic Modelling ◽  
Fisher Relation ◽  
Low Surface Brightness Galaxies ◽  
Baryonic Mass ◽  
Optical Scale

ABSTRACT We study the gas kinematics of a sample of six isolated gas-rich low surface brightness galaxies, of the class called ultra-diffuse galaxies (UDGs). These galaxies have recently been shown to be outliers from the baryonic Tully–Fisher relation (BTFR), as they rotate much slower than expected given their baryonic mass, and to have a baryon fraction similar to the cosmological mean. By means of a 3D kinematic modelling fitting technique, we show that the H i in our UDGs is distributed in ‘thin’ regularly rotating discs and we determine their rotation velocity and gas velocity dispersion. We revisit the BTFR adding galaxies from other studies. We find a previously unknown trend between the deviation from the BTFR and the exponential disc scale length valid for dwarf galaxies with circular speeds ≲ 45 km s−1, with our UDGs being at the extreme end. Based on our findings, we suggest that the high baryon fractions of our UDGs may originate due to the fact that they have experienced weak stellar feedback, likely due to their low star formation rate surface densities, and as a result they did not eject significant amounts of gas out of their discs. At the same time, we find indications that our UDGs may have higher-than-average stellar specific angular momentum, which can explain their large optical scale lengths.

scholarly journals Low Surface Brightness Galaxies and the Tully-Fisher Relation

2002 ◽  
Vol 123 (5) ◽  
pp. 2387-2401 ◽  
Author(s):  
Aeree Chung ◽  
J. H. van Gorkom ◽  
K. O’Neil ◽  
G. D. Bothun
Keyword(s):  
Surface Brightness ◽  
Low Surface Brightness ◽  
Fisher Relation ◽  
Low Surface Brightness Galaxies

scholarly journals Massive low-surface-brightness galaxies in the eagle simulation

2020 ◽  
Vol 496 (3) ◽  
pp. 3996-4016
Author(s):  
Andrea Kulier ◽  
Gaspar Galaz ◽  
Nelson D Padilla ◽  
James W Trayford
Keyword(s):  
Dark Matter ◽  
Angular Momentum ◽  
Surface Density ◽  
Surface Brightness ◽  
Initial Conditions ◽  
High Surface ◽  
Formation Rate ◽  
Dark Matter Halo ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

ABSTRACT We investigate the formation and properties of low surface brightness galaxies (LSBGs) with M* > 109.5 M⊙ in the eagle hydrodynamical cosmological simulation. Galaxy surface brightness depends on a combination of stellar mass surface density and mass-to-light ratio (M/L), such that low surface brightness is strongly correlated with both galaxy angular momentum (low surface density) and low specific star formation rate (high M/L). This drives most of the other observed correlations between surface brightness and galaxy properties, such as the fact that most LSBGs have low metallicity. We find that LSBGs are more isolated than high-surface-brightness galaxies (HSBGs), in agreement with observations, but that this trend is driven entirely by the fact that LSBGs are unlikely to be close-in satellites. The majority of LSBGs are consistent with a formation scenario in which the galaxies with the highest angular momentum are those that formed most of their stars recently from a gas reservoir co-rotating with a high-spin dark matter halo. However, the most extended LSBG discs in EAGLE, which are comparable in size to observed giant LSBGs, are built up via mergers. These galaxies are found to inhabit dark matter haloes with a higher spin in their inner regions (<0.1r200c), even when excluding the effects of baryonic physics by considering matching haloes from a dark-matter-only simulation with identical initial conditions.

scholarly journals Star Formation Rate of the Low Redshift Dwarf Galaxies J080947.50+213717.2 and J151839.94+220514.4

2021 ◽  
Vol 7 (1) ◽  
pp. 18-24
Author(s):  
S. P. Gautam ◽  
A. Silwal ◽  
A. Sedain ◽  
B. Aryal
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Strong Emission ◽  
Star Forming ◽  
Normal Galaxies ◽  
Characteristic Lines ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We performed a spectroscopic analysis of two low redshift dwarf galaxies, SDSSJ080947.50+213717.2, and SDSSJ151839.94+220514.4 selected from a catalogue of Paudel et al. 2018. The strong emission lines of the SDSS spectra of both galaxies were studied and the elements responsible were identified for those characteristic lines. The line ratio between Hα and Hβ (Hα/ Hβ) for the galaxies SDSSJ080947.50+213717.2 and SDSSJ151839.94+220514.4 was found to be 2.77 and 2.75, respectively, suggesting these are nearly dust free and star forming galaxies.. The star formation rate of the galaxies SDSSJ080947.50+213717.2 and SDSSJ151839.94+220514.4 was found to be 0.0232 M☉yr-1 and 0.05221 M☉yr-1, respectively. The ratio between NII and Hα was used to calculate the emission line metallicity, which was found to be 8.13 dex and 8.46 dex for the galaxies SDSSJ080947.50+213717.2 and SDSSJ151839.94+220514.4, respectively. From the comparison of our findings with the previous studies, slightly lower star formation rate than normal galaxies were noticed. The metallicity value for both of the galaxies were positioned in the group of low-surface-brightness galaxies of Bargvell's dwarfs..

scholarly journals Chemical Constraints, Baryonic Mass and the Chemical Evolution of Low Surface Brightness Galaxies

1999 ◽  
Vol 171 ◽  
pp. 383-389
Author(s):  
M.G. Edmunds
Keyword(s):  
Chemical Evolution ◽  
Surface Brightness ◽  
Mass Density ◽  
Intergalactic Gas ◽  
Chemical Abundances ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Baryonic Mass

AbstractA brief review of primordial helium and deuterium abundances suggests a baryonic mass density of ΩB ≈ 0.04 – 0.045 (for Ho = 70). This mass may be dominated by intergalactic gas in clusters and groups of galaxies. The observed low chemical abundances in evolved dwarf galaxies might suggest that outflow was the origin for such gas, and we make general suggestions for the interpretation of the data from the next generation of X-ray spectroscopic satellites. The effects of both outflow and inflow on the chemical evolution of galaxies is discussed, particularly in the context of low surface brightness galaxies, and we comment on their dust content.

scholarly journals Historical Introduction

1999 ◽  
Vol 171 ◽  
pp. 3-8
Author(s):  
K.C. Freeman
Keyword(s):  
Angular Momentum ◽  
Surface Brightness ◽  
Brightness Distribution ◽  
Clusters Of Galaxies ◽  
Low Surface Brightness ◽  
The Subject ◽  
Potential Impact ◽  
Fisher Relation ◽  
Low Surface Brightness Galaxies ◽  
Present View

AbstractOur ideas about the surface brightness distribution of galaxies has changed greatly since 1970. I contrast the view at that time with our present view of the subject, and then briefly discuss some topics in the studies of Low Surface Brightness Galaxies (LSBG) that I think are particularly interesting: the Tully-Fisher relation, LSBG as systems of high angular momentum, LSBG in clusters of galaxies, and the potential impact of the HIPASS survey.

scholarly journals Probes of Low Surface Brightness Galaxies through Low Frequency Spectroscopy with GMRT

2002 ◽  
Vol 199 ◽  
pp. 110-113
Author(s):  
D. Narasimha ◽  
S.M. Chitre
Keyword(s):  
Surface Brightness ◽  
Low Frequency ◽  
Rotation Velocity ◽  
Gravitational Lens ◽  
Complete Sample ◽  
Low Surface Brightness ◽  
Mass Size ◽  
Analysis Of The Images ◽  
Low Surface Brightness Galaxies ◽  
The Universe

Low Surface Brightness galaxies (LSBs) may well constitute an important component of the Universe and a good fraction of baryons may even be locked up in their gravitational potential. Existence of such massive objects was predicted from an investigation of gravitational lens systems more than a decade ago (Narasimha & Chitre, 1989). There are more compelling reasons for believing their universality based on the of the analysis of the images around the cusp caustics in some of the well-studied lenses. A complete sample of the mass, size and rotation velocity of LSBs in our neighbourhood, as well as in a limited volume at a larger redshift will be important for estimation of power spectrum as well as evolution of structures in the Universe. The GMRT type instrument is ideally suited for detection and study of the LSBs. We expect to detect 21 cm emission from around 2 to 10 LSBs per beam of GMRT dish at the level of 5 mJy flux with a survey covering 30 Mhz bandwidth, if their line width is of the order of 30 km/sec.

scholarly journals The baryonic Tully–Fisher relation in the simba simulation

2020 ◽  
Vol 498 (3) ◽  
pp. 3687-3702
Author(s):  
M Glowacki ◽  
E Elson ◽  
R Davé
Keyword(s):  
Galaxy Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Rotation Velocity ◽  
Lower Mass ◽  
Rotation Curves ◽  
Optimal Resolution ◽  
The Galaxy ◽  
Fisher Relation ◽  
Galaxy Rotation Curves

ABSTRACT We investigate the Baryonic Tully–Fisher relation (BTFR) in the $(100\, h^{-1}{\rm Mpc})^3$simba hydrodynamical galaxy formation simulation together with a higher resolution $(25\, h^{-1}{\rm Mpc})^3$simba run, for over 10 000 disc-dominated, H i-rich galaxies. We generate simulated galaxy rotation curves from the mass distribution, which we show yields similar results to using the gas rotational velocities. From this, we measure the galaxy rotation velocity Vcirc using four metrics: $V_{\rm max}, V_{\rm flat}, V_{2R_e},$ and Vpolyex. We compare the predicted BTFR to the SPARC observational sample and find broad agreement. In detail, however, simba is biased towards higher Vcirc by up to 0.1 dex. We find evidence for the flattening of the BTFR in Vcirc > 300  km s−1 galaxies, in agreement with recent observational findings. simba’s rotation curves are more peaked for lower mass galaxies, in contrast with observations, suggesting overly bulge-dominated dwarf galaxies in our sample. We investigate for residuals around the BTFR versus H i mass, stellar mass, gas fraction, and specific star formation rate, which provide testable predictions for upcoming BTFR surveys. simba’s BTFR shows sub-optimal resolution mass convergence, with the higher resolution run lowering V in better agreement with data.

A Survey for Low Surface Brightness Galaxies around M31. II. The Newly Discovered Dwarf Andromeda VI

1999 ◽  
Vol 118 (3) ◽  
pp. 1220-1229 ◽  
Author(s):  
Taft E. Armandroff ◽  
George H. Jacoby ◽  
James E. Davies
Keyword(s):  
Surface Brightness ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies
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