Properties of low Surface Brightness Galaxies

1996 ◽  
Vol 171 ◽  
pp. 356-356
Author(s):  
W.J.G. de Blok ◽  
J.M. Van Der Hulst ◽  
S.S. McGaugh

We have been working on multiband surface photometry, spectrophotometry and Hi synthesis data for 20 Low Surface Brightness (LSB) galaxies. LSB galaxies are well described by disks with an average central surface brightness of ∼ 23.4B-mag arcsec–2. They have scale lengths typical for high surface brightness (HSB) galaxies, though a large range of sizes is present. Their colours are blue, especially at the red side of the spectrum, where they are significantly bluer than HSB galaxies (de Blok et al. 1995a). Modelling and measurements of gas abundances (McGaugh 1994) suggests a low, stochastic star formation rate, and a lack of a large old population. The Hi surface densities are a factor of three lower than those in HSB galaxies (de Blok et al 1995b). However the difference is not as large as in the optical. The Hi disks are considerably larger, relative to the optical disks, than in HSB galaxies. The gas mass fraction is higher, indicating slow evolution. Star formation is inhibited by the low surface densities which are typically below the critical treshold as stipulated by Toomre's gravitational instability criterion. The rotation curves rise gradually, and are observed to flatten out only in a few cases. Often they still rise at the last measured point, or remain solid body through-out. Preliminary mass models suggest extended low density dark matter halos, with baryon dominated inner regions. The inferred evolution for LSB galaxies shows mass and density are fundamental parameters in determining a galaxy's evolutionary fate.

2020 ◽  
Vol 493 (1) ◽  
pp. 55-69 ◽  
Author(s):  
J E Young ◽  
Rachel Kuzio de Naray ◽  
Sharon X Wang

ABSTRACT We present the star-formation history of the low surface brightness (LSB) galaxy UGC 628 as part of the MUSCEL program (MUltiwavelength observations of the Structure, Chemistry, and Evolution of LSB galaxies). The star-formation histories of LSB galaxies represent a significant gap in our knowledge of galaxy assembly, with implications for dark matter / baryon feedback, IGM gas accretion, and the physics of star formation in low metallicity environments. Our program uses ground-based IFU spectra in tandem with space-based UV and IR imaging to determine the star-formation histories of LSB galaxies in a spatially resolved fashion. In this work we present the fitted history of our first target to demonstrate our techniques and methodology. Our technique splits the history of this galaxy into 15 semilogarithmically spaced time-steps. Within each time-step the star-formation rate of each spaxel is assumed constant. We then determine the set of 15 star-formation rates that best recreate the spectra and photometry measured in each spaxel. Our main findings with respect to UGC 628 are: (i) the visible properties of UGC 628 have varied over time, appearing as a high surface brightness spiral earlier than 8 Gyr ago and a starburst galaxy during a recent episode of star formation several tens of Myr ago, (ii) the central bar/core region was established early, around 8–10 Gyr ago, but has been largely inactive since, and (iii) star formation in the past 3 Gyr is best characterized as patchy and sporadic.


2019 ◽  
Vol 490 (4) ◽  
pp. 5451-5477 ◽  
Author(s):  
Chiara Di Paolo ◽  
Paolo Salucci ◽  
Adnan Erkurt

ABSTRACT We investigate the properties of the baryonic and the dark matter components in low surface brightness (LSB) disc galaxies, with central surface brightness in the B band $\mu _0 \ge 23 \, \mathrm{mag \, arcsec}^{-2}$. The sample is composed of 72 objects, whose rotation curves show an orderly trend reflecting the idea of a universal rotation curve (URC) similar to that found in the local high surface brightness (HSB) spirals in previous works. This curve relies on the mass modelling of the co-added rotation curves, involving the contribution from an exponential stellar disc and a Burkert cored dark matter halo. We find that the dark matter is dominant especially within the smallest and less luminous LSB galaxies. Dark matter haloes have a central surface density $\Sigma _0 \sim 100 \, \mathrm{M}_{\odot } \, \mathrm{pc}^{-2}$, similar to galaxies of different Hubble types and luminosities. We find various scaling relations among the LSBs structural properties which turn out to be similar but not identical to what has been found in HSB spirals. In addition, the investigation of these objects calls for the introduction of a new luminous parameter, the stellar compactness C* (analogously to a recent work by Karukes & Salucci), alongside the optical radius and the optical velocity in order to reproduce the URC. Furthermore, a mysterious entanglement between the properties of the luminous and the dark matter emerges.


2007 ◽  
Vol 3 (S244) ◽  
pp. 266-273
Author(s):  
K. O'Neil

AbstractMassive low surface brightness galaxies have disk central surface brightnesses at least one magnitude fainter than the night sky, but total magnitudes and masses that show they are among the largest galaxies known. Like all low surface brightness (LSB) galaxies, massive LSB galaxies are often in the midst of star formation yet their stellar light has remained diffuse, raising the question of how star formation is proceeding within these galaxies. We have undertaken a multi-wavelength study to clarify the structural parameters and stellar and gas content of these enigmatic systems. The results of these studies, which include HI, CO, optical, near UV, and far UV images of the galaxies will provide the most in depth study done to date of how, when, and where star formation proceeds within this unique subset of the galaxy population.


Author(s):  
James M. Schombert ◽  
Stacy McGaugh

AbstractSurface photometry at 3.6 μm is presented for 61 low surface brightness (LSB) galaxies (μo<19 3.6 μm mag arcsecs−2). The sample covers a range of luminosity from −11 to −22 in M3.6 and size from 1 to 25 kpc. The morphologies in the mid-IR are comparable to those in the optical with 3.6 μm imaging reaches similar surface brightness depth as ground-based optical imaging. A majority of the resulting surface brightness profiles are single exponential in shape with very few displaying upward or downward breaks. The mean V − 3.6 colour of LSB is 2.3 with a standard deviation of 0.5. Colour-magnitude and two-colour diagrams are well matched to models of constant star formation, where the spread in colour is due to small changes in the star formation rate (SFR) over the last 0.5 Gyrs as also suggested by the specific SFR measured by Hα.


1999 ◽  
Vol 171 ◽  
pp. 253-260 ◽  
Author(s):  
John J. Salzer ◽  
Stuart A. Norton

AbstractWe analyze deep CCD images of nearby Blue Compact Dwarf (BCD) galaxies in an attempt to understand the nature of the progenitors which are hosting the current burst of star formation. In particular, we ask whether BCDs are hosted by normal or low-surface-brightness dI galaxies. We conclude that BCDs are in fact hosted by gas-rich galaxies which populate the extreme high-central-mass-density end of the dwarf galaxy distribution. Such galaxies are predisposed to having numerous strong bursts of star formation in their central regions. In this picture, BCDs can only occur in the minority of dwarf galaxies, rather than being a common phase experienced by all gas-rich dwarfs.


2011 ◽  
Vol 7 (S284) ◽  
pp. 138-140
Author(s):  
Philip Günster ◽  
Dominik J. Bomans

AbstractUGC 12281 has been classified as having a pure disk and being a low surface brightness galaxy (LSBG), thus being an obvious member of the so-called superthin galaxies. At the same time it represents an extremely untypical type of LSBG due to its remarkable amount of current star formation and evidence for extraplanar ionized gas. This makes it become a perfect tool to investigate the triggering of star formation in LSB galaxies, located in an alleged isolated area. By means of deep photometry and long-slit spectroscopy we analyse the Hα halo and verify the existence of a potential dwarf companion which we found on processed SDSS images.


2020 ◽  
Vol 496 (3) ◽  
pp. 3996-4016
Author(s):  
Andrea Kulier ◽  
Gaspar Galaz ◽  
Nelson D Padilla ◽  
James W Trayford

ABSTRACT We investigate the formation and properties of low surface brightness galaxies (LSBGs) with M* &gt; 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 (&lt;0.1r200c), even when excluding the effects of baryonic physics by considering matching haloes from a dark-matter-only simulation with identical initial conditions.


2007 ◽  
Vol 3 (S244) ◽  
pp. 352-353
Author(s):  
M. Das ◽  
S. S. McGaugh ◽  
N. Kantharia ◽  
S. N. Vogel

AbstractWe present preliminary results of a study of the low frequency radio continuum emission from the nuclei of Giant Low Surface Brightness (LSB) galaxies. We have mapped the emission and searched for extended features such as radio lobes/jets associated with AGN activity. LSB galaxies are poor in star formation and generally less evolved compared to nearby bright spirals. This paper presents low frequency observations of 3 galaxies; PGC 045080 at 1.4 GHz, 610 MHz, 325MHz, UGC 1922 at 610 MHz and UGC 6614 at 610 MHz. The observations were done with the GMRT. Radio cores as well as extended structures were detected and mapped in all three galaxies; the extended emission may be assocated with jets/lobes associated with AGN activity. Our results indicate that although these galaxies are optically dim, their nuclei can host AGN that are bright in the radio domain.


2019 ◽  
Vol 490 (3) ◽  
pp. 3772-3785
Author(s):  
Luis Enrique Pérez-Montaño ◽  
Bernardo Cervantes Sodi

ABSTRACT We select a volume-limited sample of galaxies derived from the SDSS DR7 to study the environment of low surface brightness (LSB) galaxies at different scales, as well as several physical properties of the dark matter haloes where the LSB galaxies of the sample are embedded. To characterize the environment, we make use of a number of publicly available value-added galaxy catalogues. We find a slight preference for LSB galaxies to be found in filaments instead of clusters, with their mean distance to the nearest filament typically larger than for high surface brightness (HSB) galaxies. The fraction of isolated central LSB galaxies is higher than the same fraction for HSB ones, and the density of their local environment lower. The stellar-to-halo mass ratio using four different estimates is up to ∼20 per cent for HSB galaxies. LSB central galaxies present more recent assembly times when compared with their HSB counterparts. Regarding the λ spin parameter, using six different proxies for its estimation, we find that LSB galaxies present systematically larger values of λ than the HSB galaxy sample, and constructing a control sample with direct kinematic information drawn from ALFALFA, we confirm that the spin parameter of LSB galaxies is 1.6–2 times larger than the one estimated for their HSB counterparts.


1999 ◽  
Vol 171 ◽  
pp. 229-236 ◽  
Author(s):  
Ben Moore ◽  
George Lake ◽  
Joachim Stadel ◽  
Thomas Quinn

AbstractWe follow the evolution of disk galaxies within a cluster that forms hierarchically in a standard cold dark matter N-body simulation. At a redshift z = 0.5 we select several dark matter halos that have quiet merger histories and are about to enter the newly forming cluster environment. The halos are replaced with equilibrium high resolution model spirals that are constructed to represent luminous examples of low surface brightness (LSB) and high surface brightness (HSB) galaxies. Whilst the models have the same total luminosity, ~ L*, they have very different internal mass profiles, core radii and disk scale lengths, however they all lie at the same place on the Tully-Fisher relation. Due to their “soft” central potentials, LSB galaxies evolve dramatically under the influence of rapid encounters with substructure and strong tidal shocks from the global cluster potential - galaxy harassment. As much as 90% of the LSB disk stars are tidally stripped and congregate in large diffuse tails that trace the orbital path of the galaxy and form the diffuse intra-cluster light. The bound stellar remnants closely resemble the dwarf spheroidals (dE’s) that populate nearby clusters, with large scale lengths and low central surface brightness.


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