scholarly journals 12CO(J=3→2) detections in bulges of low surface brightness galaxies with APEX

2007 ◽  
Vol 3 (S245) ◽  
pp. 191-192
Author(s):  
Gaspar Galaz ◽  
Paulo Cortes ◽  
Leonardo Bronfman ◽  
Monica Rubio
Keyword(s):  
Surface Brightness ◽  
High Surface ◽  
Rotational Transition ◽  
Main Beam ◽  
Molecular Gas ◽  
Gas Temperature ◽  
Upper Limits ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
First Time

AbstractUsing the APEX sub-millimeter telescope we have detected for the first time the CO rotational transition 12CO(J=3→2) in two of five low surface brightness galaxies. For galaxies with positive detection, the emission is detected in their bulges, with measured gas velocity dispersion of about 80 km/s and observed main-beam brightness temperature TM B ~ 10 mK. Using a standard CO to H2 conversion factor, we are able to estimate molecular gas masses for LSBs with positive detections, and upper limits for those LSBs with negative detections. Assuming a higher gas temperature for the generation of the 12CO(J=3→2) line compared to that for the 12CO(J=1→0) one, results suggest that a warm molecular gas component is present in bulges, indicating a radiation field preventing the formation of large cooler amounts of molecular gas, compared to high surface brightness galaxies with higher metallicity and likely more dust.

scholarly journals Molecular Gas and Star-formation in Low Surface Brightness Galaxies

2017 ◽  
Vol 154 (3) ◽  
pp. 116 ◽  
Author(s):  
Tian-Wen Cao ◽  
Hong Wu ◽  
Wei Du ◽  
Feng-Jie Lei ◽  
Ming Zhu ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Molecular Gas ◽  
Low Surface Brightness ◽  
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 The σc — Vcirc correlation in high and low surface brightness galaxies

2004 ◽  
Vol 220 ◽  
pp. 339-340 ◽  
Author(s):  
A. Pizzella ◽  
E. Dalla Bontà ◽  
E. M. Corsini ◽  
L. Coccato ◽  
F. Bertola
Keyword(s):  
Surface Brightness ◽  
Velocity Dispersion ◽  
Spiral Galaxies ◽  
High Surface ◽  
Linear Scale ◽  
High Surface Brightness ◽  
Circular Velocity ◽  
Straight Line ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We investigate the relation between the central velocity dispersion, σc, and the circular velocity, Vcirc, in galaxies. in addition to previously obtained data, we consider an observationally homogeneus sample of 52 high surface brightness and 11 low surface brightness spiral galaxies. We performed a straight line regression analysis in a linear scale, finding a good fit, also for low σc galaxies, always rejected in the previous studies. Low surface brightness galaxies seem to behave differently, showing either higher values of Vcirc or lower values of σc with respect to their high surface brightness counterparts.

scholarly journals Stellar Populations of Dwarf Galaxies

1995 ◽  
Vol 164 ◽  
pp. 430-431
Author(s):  
Elchanan Almoznino ◽  
Noah Brosch
Keyword(s):  
Surface Brightness ◽  
Dwarf Galaxies ◽  
High Surface ◽  
Stellar Populations ◽  
Virgo Cluster ◽  
Original Sample ◽  
High Surface Brightness ◽  
Brightness Level ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

We selected a sample of dwarf galaxies in the Virgo cluster from the original catalog of Bingelli, Sandage and Tamman (1985), which have been measured at 21 cm by Hoffman et al. (1987). The original sample was selected to have both high surface brightness objects (classified as BCD or anything/BCD), and low surface brightness galaxies (classified as ImIII, ImIV or ImV). An additional selection was done on the total amount of HI, as given in Hoffman et al. We selected from each surface brightness group objects with high HI content (flux integral larger than a set threshold), and others with low HI content. We thus defined four samples differing in surface brightness level and total HI content.

scholarly journals Observational insights on the origin of giant low surface brightness galaxies

2021 ◽  
Vol 503 (1) ◽  
pp. 830-849
Author(s):  
Anna S Saburova ◽  
Igor V Chilingarian ◽  
Anastasia V Kasparova ◽  
Olga K Sil’chenko ◽  
Kirill A Grishin ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
High Surface ◽  
Dark Matter Halo ◽  
High Mass ◽  
Formation Mechanisms ◽  
Orbital Parameters ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

ABSTRACT Giant low surface brightness galaxies (gLSBGs) with dynamically cold stellar discs reaching the radius of 130 kpc challenge currently considered galaxy formation mechanisms. We analyse new deep long-slit optical spectroscopic observations, archival optical images, and published Hi and optical spectroscopic data for a sample of seven gLSBGs, for which we performed mass modelling and estimated the parameters of dark matter haloes assuming the Burkert dark matter density profile. Our sample is not homogeneous by morphology, parameters of stellar populations, and total mass, however, six of seven galaxies sit on the high-mass extension of the baryonic Tully–Fisher relation. In UGC 1382, we detected a global counterrotation of the stellar high surface brightness (HSB) disc with respect to the extended LSB disc. In UGC 1922 with signatures of a possible merger, the gas counterrotation is seen in the inner disc. Six galaxies host active galactic nuclei, three of which have the estimated black hole masses substantially below those expected for their (pseudo-)bulge properties suggesting poor merger histories. Overall, the morphology, internal dynamics, and low star formation efficiency in the outer discs indicate that the three formation scenarios shape gLSBGs: (i) a two-stage formation when an HSB galaxy is formed first and then grows an LSB disc by accreting gas from an external supply; (ii) an unusual shallow and extended dark matter halo; (iii) a major merger with fine-tuned orbital parameters and morphologies of the merging galaxies.

scholarly journals Morphology and Stellar Populations in the Gas-Rich, Giant LSBGs

1999 ◽  
Vol 171 ◽  
pp. 191-195 ◽  
Author(s):  
P. Knezek
Keyword(s):  
Entire Range ◽  
Surface Brightness ◽  
Spiral Galaxies ◽  
High Surface ◽  
Nuclear Spectroscopy ◽  
Nuclear Activity ◽  
High Surface Brightness ◽  
Low Surface Brightness ◽  
Show Evidence ◽  
Low Surface Brightness Galaxies

AbstractAn unexpected characteristic of low surface brightness galaxies (LSBGs) is that a significant number are massive and possess substantial amounts of atomic gas. We present preliminary results of an ongoing program to obtain BVRIJHK imaging, along with some nuclear spectroscopy, of a well-defined sample of LSBGs which are gas-rich and of similar size to giant, high surface brightness spiral galaxies (HSBGs). These LSBGs span the entire range of Hubble disk morphologies. While their disks are bluer, on average, than comparable HSBGs, the optical morphology of massive LSBGs indicates that many of these systems have undergone previous star formation episodes. They typically have long disk scale lengths, and range from MB = −16 to −22 (H0 = 75 km s−1 Mpc−1). About half of the LSBGs with bulges show evidence of nuclear activity, and ~30% appear to be barred. These massive, gas-rich LSBGs apparently have varied, and often complex, evolutionary histories.

scholarly journals The Structure of the Multi-Phase ISM in Low Surface Brightness Galaxies

1999 ◽  
Vol 171 ◽  
pp. 237-244 ◽  
Author(s):  
M. Spaans
Keyword(s):  
Carbon Monoxide ◽  
Galaxy Evolution ◽  
Molecular Hydrogen ◽  
Surface Brightness ◽  
Ambient Pressure ◽  
Upper Limits ◽  
Low Surface Brightness ◽  
Multi Phase ◽  
Low Surface Brightness Galaxies ◽  
Formation Efficiency

AbstractThe multi-phase structure of the interstellar medium in low surface brightness galaxies is investigated and compared to observations. It is found that the ambient pressure and metallicity very strongly influence the abundances of molecular hydrogen and carbon monoxide. The emissivity of the latter is computed and found to agree naturally with the upper limits measured for low surface brightness galaxies. The implications for star formation efficiency and galaxy evolution are discussed.

scholarly journals The universal rotation curve of low surface brightness galaxies – IV. The interrelation between dark and luminous matter

2019 ◽  
Vol 490 (4) ◽  
pp. 5451-5477 ◽  
Author(s):  
Chiara Di Paolo ◽  
Paolo Salucci ◽  
Adnan Erkurt
Keyword(s):  
Dark Matter ◽  
Surface Brightness ◽  
Rotation Curve ◽  
High Surface ◽  
Dark Matter Halo ◽  
Rotation Curves ◽  
Central Surface ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies ◽  
Lsb Galaxies

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.

scholarly journals The origin of low-surface-brightness galaxies in the dwarf regime

2021 ◽  
Vol 502 (3) ◽  
pp. 4262-4276
Author(s):  
R A Jackson ◽  
G Martin ◽  
S Kaviraj ◽  
M Ramsøy ◽  
J E G Devriendt ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
High Surface ◽  
Stellar Mass ◽  
Current Data ◽  
Sloan Digital Sky Survey ◽  
Data Sets ◽  
Low Surface Brightness ◽  
Gas Accretion ◽  
Low Surface Brightness Galaxies

ABSTRACT Low-surface-brightness galaxies (LSBGs) – defined as systems that are fainter than the surface-brightness limits of past wide-area surveys – form the overwhelming majority of galaxies in the dwarf regime (M⋆ < 109 M⊙). Using NewHorizon, a high-resolution cosmological simulation, we study the origin of LSBGs and explain why LSBGs at similar stellar mass show the large observed spread in surface brightness. NewHorizon galaxies populate a well-defined locus in the surface brightness–stellar mass plane, with a spread of ∼3 mag arcsec−2, in agreement with deep Sloan Digital Sky Survey (SDSS) Stripe 82 data. Galaxies with fainter surface brightnesses today are born in regions of higher dark matter density. This results in faster gas accretion and more intense star formation at early epochs. The stronger resultant supernova feedback flattens gas profiles at a faster rate, which, in turn, creates shallower stellar profiles (i.e. more diffuse systems) more rapidly. As star formation declines towards late epochs ( z < 1), the larger tidal perturbations and ram pressure experienced by these systems (due to their denser local environments) accelerate the divergence in surface brightness, by increasing their effective radii and reducing star formation, respectively. A small minority of dwarfs depart from the main locus towards high surface brightnesses, making them detectable in past wide surveys (e.g. standard-depth SDSS images). These systems have anomalously high star formation rates, triggered by recent fly-by or merger-driven starbursts. We note that objects considered extreme or anomalous at the depth of current data sets, e.g. ‘ultra-diffuse galaxies’, actually dominate the predicted dwarf population and will be routinely visible in future surveys like the Legacy Survey of Space and Time (LSST).

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