scholarly journals Stellar Populations and the Star Formation Histories of LSB Galaxies: IV Spitzer Surface Photometry of LSB Galaxies

2014 ◽  
Vol 31 ◽  
Author(s):  
James M. Schombert ◽  
Stacy McGaugh
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Surface Photometry ◽  
Low Surface Brightness ◽  
The Mean ◽  
Star Formation Histories ◽  
Lsb Galaxies ◽  
Single Exponential

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.

scholarly journals A recent starbust in the low surface brightness galaxy UGC 628

2020 ◽  
Vol 493 (1) ◽  
pp. 55-69 ◽  
Author(s):  
J E Young ◽  
Rachel Kuzio de Naray ◽  
Sharon X Wang
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
High Surface ◽  
Star Formation History ◽  
Starburst Galaxy ◽  
Time Step ◽  
Low Surface Brightness ◽  
History Of ◽  
Star Formation Histories ◽  
Lsb Galaxies

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.

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
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Gravitational Instability ◽  
High Surface ◽  
Formation Rate ◽  
Instability Criterion ◽  
Fundamental Parameters ◽  
Central Surface ◽  
Low Surface Brightness ◽  
Lsb Galaxies

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.

scholarly journals Properties of galaxies with an offset between the position angles of the major kinematic and photometric axes

2020 ◽  
Vol 634 ◽  
pp. A26 ◽  
Author(s):  
L. S. Pilyugin ◽  
E. K. Grebel ◽  
I. A. Zinchenko ◽  
J. M. Vílchez ◽  
F. Sakhibov ◽  
...  
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Velocity Fields ◽  
Oxygen Abundance ◽  
Star Forming ◽  
Measured Position ◽  
Central Oxygen ◽  
Straight Lines

We derive the photometric, kinematic, and abundance characteristics of 18 star-forming MaNGA galaxies with fairly regular velocity fields and surface brightness distributions and with a large offset between the measured position angles of the major kinematic and photometric axes, ΔPA ≳ 20°. The aim is to examine if there is any other distinctive characteristic common to these galaxies. We found morphological signs of interaction in some (in 11 out of 18) but not in all galaxies. The observed velocity fields show a large variety; the maps of the isovelocities vary from an hourglass-like appearance to a set of straight lines. The position angles of the major kinematic axes of the stellar and gas rotations are close to each other. The values of the central oxygen abundance, radial abundance gradient, and star formation rate are distributed within the intervals defined by galaxies with small (no) ΔPA of similar mass. Thus, we do not find any specific characteristic common to all galaxies with large ΔPA. Instead, the properties of these galaxies are similar to those of galaxies with small (no) ΔPA. This suggests that either the reason responsible for the large ΔPA does not influence other characteristics or the galaxies with large ΔPA do not share a common origin, they can, instead, originate through different channels.

scholarly journals Morphometry as a probe of the evolution of jellyfish galaxies: evidence of broadening in the surface brightness profiles of ram-pressure stripping candidates in the multicluster system A901/A902

2020 ◽  
Vol 500 (1) ◽  
pp. 40-53
Author(s):  
Fernanda Roman-Oliveira ◽  
Ana L Chies-Santos ◽  
Fabricio Ferrari ◽  
Geferson Lucatelli ◽  
Bruno Rodríguez Del Pino
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Quantitative Measurement ◽  
Star Formation Rate ◽  
Hubble Space Telescope ◽  
Formation Rate ◽  
Structural Evolution ◽  
Star Forming ◽  
Irregular Structures ◽  
Ram Pressure

ABSTRACT We explore the morphometric properties of a group of 73 ram-pressure stripping candidates in the A901/A902 multicluster system, at z∼ 0.165, to characterize the morphologies and structural evolution of jellyfish galaxies. By employing a quantitative measurement of morphometric indicators with the algorithm morfometryka on Hubble Space Telescope (F606W) images of the galaxies, we present a novel morphology-based method for determining trail vectors. We study the surface brightness profiles and curvature of the candidates and compare the results obtained with two analysis packages, morfometryka and iraf/ellipse on retrieving information of the irregular structures present in the galaxies. Our morphometric analysis shows that the ram-pressure stripping candidates have peculiar concave regions in their surface brightness profiles. Therefore, these profiles are less concentrated (lower Sérsic indices) than other star-forming galaxies that do not show morphological features of ram-pressure stripping. In combination with morphometric trail vectors, this feature could both help identify galaxies undergoing ram-pressure stripping and reveal spatial variations in the star formation rate.

scholarly journals An older, more quiescent universe from panchromatic SED fitting of the 3D-HST survey

2019 ◽  
Vol 15 (S352) ◽  
pp. 99-102
Author(s):  
Joel Leja ◽  
Benjamin D. Johnson ◽  
Charlie Conroy ◽  
Pieter van Dokkum ◽  
Joshua S. Speagle ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Complex Scaling ◽  
Physical Systems ◽  
Scaling Relationships ◽  
Highly Correlated ◽  
Bayesian Inference Framework ◽  
Stellar Masses ◽  
Star Formation Histories

AbstractGalaxies are complicated physical systems which obey complex scaling relationships; as a result, properties measured from broadband photometry are often highly correlated, degenerate, or both. Therefore, the accuracy of basic properties like stellar masses and star formation rates (SFRs) depend on the accuracy of many second-order galaxy properties, including star formation histories (SFHs), stellar metallicities, dust properties, and many others. Here, we re-assess measurements of galaxy stellar masses and SFRs using a 14-parameter physical model built in the Prospector Bayesian inference framework. We find that galaxies are ∼0.2 dex more massive and have ∼0.2 dex lower star formation rates than classic measurements. These measurements lower the observed cosmic star formation rate density and increase the observed buildup of stellar mass, finally bringing these two metrics into agreement at the factor-of-two level at 0.5 < z < 2.5.

scholarly journals Gas-rich LSB Galaxies – Progenitors of Blue Compact Dwarfs?

1999 ◽  
Vol 171 ◽  
pp. 253-260 ◽  
Author(s):  
John J. Salzer ◽  
Stuart A. Norton
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Mass Density ◽  
Central Mass ◽  
Galaxy Distribution ◽  
Low Surface Brightness ◽  
Central Regions ◽  
Lsb Galaxies

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.

scholarly journals On the nature of the peculiar superthin LSB galaxy UGC 12281

2011 ◽  
Vol 7 (S284) ◽  
pp. 138-140
Author(s):  
Philip Günster ◽  
Dominik J. Bomans
Keyword(s):  
Star Formation ◽  
Surface Brightness ◽  
Ionized Gas ◽  
Low Surface Brightness ◽  
Lsb Galaxies

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.

scholarly journals The evolution of the spiral galaxy M51a

2015 ◽  
Vol 11 (S319) ◽  
pp. 129-129
Author(s):  
Xiaoyu Kang ◽  
Fenghui Zhang ◽  
Ruixiang Chang
Keyword(s):  
Star Formation ◽  
Surface Density ◽  
Evolutionary History ◽  
Surface Brightness ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Molecular Gas ◽  
Peak Time ◽  
Model Predictions ◽  
Inside Out

AbstractA simple model for M51a is constructed to explore its evolutionary history by assuming its disk grows from continuous gas infall, which is shaped by a free parameter-the infall-peak time tp. By adopting a constant infall-peak time tp = 7.0Gyr, our model predictions can reproduce most of the observed constraints and still show that the disk of M51a forms inside-out. Our results also show that the current molecular gas surface density, the star-formation rate and the UV-band surface brightness are important quantities to trace the effect of recent interactions on galactic star-formation process.

scholarly journals Spectral synthesis of stellar populations in the 3D era: The CALIFA experience

2014 ◽  
Vol 10 (S309) ◽  
pp. 93-98
Author(s):  
R. Cid Fernandes ◽  
E. A. D. Lacerda ◽  
R. M. González Delgado ◽  
N. Vale Asari ◽  
R. García-Benito ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Spectral Synthesis ◽  
Mass Density ◽  
Formation Rate ◽  
Stellar Populations ◽  
Data Cubes ◽  
The Mean ◽  
Stellar Masses ◽  
Star Formation Histories

AbstractMethods to recover the fossil record of galaxy evolution encoded in their optical spectra have been instrumental in processing the avalanche of data from mega-surveys along the last decade, effectively transforming observed spectra onto a long and rich list of physical properties: from stellar masses and mean ages to full star formation histories. This promoted progress in our understanding of galaxies as a whole. Yet, the lack of spatial resolution introduces undesirable aperture effects, and hampers advances on the internal physics of galaxies. This is now changing with 3D surveys. The mapping of stellar populations in data-cubes allows us to figure what comes from where, unscrambling information previously available only in integrated form. This contribution uses our starlight-based analysis of 300 CALIFA galaxies to illustrate the power of spectral synthesis applied to data-cubes. The selected results highlighted here include: (a) The evolution of the mass-metallicity and mass-density-metallicity relations, as traced by the mean stellar metallicity. (b) A comparison of star formation rates obtained from Hα to those derived from full spectral fits. (c) The relation between star formation rate and dust optical depth within galaxies, which turns out to mimic the Schmidt-Kennicutt law. (d) PCA tomography experiments.

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