Relation Between BCDS and Blue LSBGS

Bergvall, Nils; Östlin, Göran; Pharasyn, Arnaud; Rönnback, Jari; Masegosa, J.

doi:10.1017/s1539299600020086

Cited by 20 publications

(38 citation statements)

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“…These may nevertheless be splitted into HSB or LSB galaxies according to the clear-cut criterium given above (and that is included in Table 1). Similar diagrams for spiral galaxies data in other bandpasses are shown -with explicit visualization of this luminosity independent high-versus-low surface brightness dependence-in, e.g., Bergvall et al (1999) (<µ 0,B >≈ 23.0 mag arcsec −2 with a focus on LSB galaxies), Zhong et al (2008) (<µ 0,B >≈ 22.0 mag arcsec −2 , i.e., in the vicinity of the original Freeman law value 21.65), Janowiecki & Salzer (2014) (<µ 0,B >≈ 20.7 mag arcsec −2 for BCD galaxies), Fathi (2010) (<µ 0,R >≈ 20.2 mag arcsec −2 ), or Courteau et al (2007) and Dutton et al (2007) (<µ 0,I >≈ 19.0 mag arcsec −2 , for dominantly brighter galaxies). At all bandpasses, there's a characteristic global mean extrapolated central SB irrespective of absolute magnitude; and there seemingly is some trend for this mean surface brightness to become brighter towards longer wave lengths.…”

Section: Loci Of Constant Central Surface Brightness or Compactnesssupporting

confidence: 64%

Structure-dynamics relations for late-type spiral and dwarf irregular galaxies revisited

Parodi¹

2018

Preprint

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Scaling relations among structural and kinematical features of 79 late-type spiral and dwarf irregular galaxies of the SPARC sample are revisited or newly established. The mean central surface brightness µ 0 <µ 0,[3.6] >= 19.63 ± 0.11 mag arcsec −2 allows for a clear-cut distinction between low and high surface brightness galaxies. At a given luminosity, LSB galaxies are more extended than HSB galaxies and the rotation curves have smaller inner circular velocity gradients dv(R d )/dr at one disk scale length R d . Irrespective of luminosity, the geometry of rotation curves is characterized by the relation dv(R d )/dr ≈ v max /R max , with v max being the maximum circular velocity reached at R max . For the rotation curve decompositions disk mass-tolight ratios are restricted to have constant, but semi-free best-fit values 0.2, 0.5, or 0.8 M /L at [3.6]; they exhibit an asymmetric bimodal distribution with the dominant peak located at the median value of 0.2 (minimum disks) and with the subdominant peak at 0.8 (maximum disks). Assuming dark matter halos of Burkert and of pseudo-isothermal (PITS) type, the former provide better fits for about two thirds of all galaxies. While the halo core densities ρ 0 are about equal, the core radii r 0 of PITS halos are systematically lower by a factor of about 0.6 as compared with those of the Burkert type. Focussing on the Burkert halo, the baryonic mass fraction at intermediate radii is included to address both an adjusted baryonic Tully-Fisher relation and the significance of deviations from the mean radial acceleration relation. The average radial decrease of the baryonic mass fraction within galaxies is quantified. The Burkert halo parameters obey ρ 0 ∝ r −1.5±0.1 0 with considerable scatter, but allowing v max as a third variable we find ρ 0 ∝ r −1.84±0.07 0 v 2.00±0.11 max with small scatter. The halo central surface density ρ 0 r 0 , with a sample median <ρ 0 r 0 > ≈ 121 M pc −2 (σ = 112), weakly correlates with µ 0 and with compactness C and strongly correlates with the observed radial acceleration g obs = v 2 obs (r)/r at different galactocentric radii. Consequently, because R max ∝ r 0 , we have a tight central halo column density versus maximum circular velocity relation v 2 max ∝ ρ 0 r 2 0 . Halo cores barely extend over the luminous disk, but their sizes do not correlate with the optical radii. We introduce an alternative to a prominent conventional universal rotation curve; it is based on the non-singular total matter density profile ρ total (r) = (v 2 max /4πGr 2 ) 1 − (1 − r/r c ) exp(−r/r c ) 2 , with the scaling parameter r c correlating with the halo core size r 0 . Fitting the synthetic URC to a selection of galaxies, the co-added doubly-normalized rotation curves exhibit a high degree of similarity. A couple of analytic URC decompositions into a baryonic disk and a dark matter component is accomplished.

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Section: Loci Of Constant Central Surface Brightness or Compactnesssupporting

confidence: 64%

Structure-dynamics relations for late-type spiral and dwarf irregular galaxies revisited

Parodi¹

2018

Preprint

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“…One wishes to compare the integrated colors of the main components (host galaxy and polar structure, shown in Table 3) with those of standard morphological galaxy types, and check whether differences in colors are related to dust absorption or to different stellar populations. NIR colors -The NIR colors of the central spheroid and the polar structure are compared with those of (1) standard early-type galaxies in the Fornax and Virgo clusters (Persson et al, 1979), ( 2) spirals (Giovanardi & Hunt, 1996;Frogel, 1985;de Jong & van der Kruit, 1994), (3) dwarf ellipticals (Thuan, 1985), and (4) low surface brightness galaxies (Bergvall et al 1999). The J-H vs. H-K plot in Fig.…”

Section: Using Colors To Date the Stellar Populations Of Ngc 4650amentioning

confidence: 99%

The Puzzle of the Polar Structure in NGC 4650A

Iodice

Arnaboldi

Lucia

et al. 2002

The Astronomical Journal

113

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This work presents new surface photometry and two-dimensional modeling of the light distribution of the Polar Ring Galaxy NGC 4650A, based on near-infrared (NIR) observations and high resolution optical imaging acquired during the Hubble Heritage 1 program.The NIR and optical integrated colors of the S0 and the polar ring, and their scale parameters, are compared with those for standard galaxy morphological types. The polar structure appears to be a disk of a very young age, while the colors and light distribution of the host galaxy do not resemble that of a typical early-type system. We compare these observational results with the predictions from different formation scenarios for polar ring galaxies. The peculiarities of the central S0 galaxy, the polar disk structure and stellar population ages suggest that the polar ring galaxy NGC 4650A may be the result of a dissipative merger event, rather than of an accretion process.

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“…LSB galaxies are believed to have thinner discs (Matthews 2000;Bizyaev & Mitronova 2002Khoperskov et al 2010) with larger exponential scalelengths (Zhong et al 2008;Bothun et al 1997;Bergvall et al 1999) than "normal" galaxies. The bulges occur very rarely in LSB galaxies and are smaller in size than those in classical spirals.…”

Section: Introductionmentioning

confidence: 99%

A portrait of Malin 2: a case study of a giant low surface brightness galaxy

Kasparova¹,

Saburova²,

Katkov³

et al. 2013

Monthly Notices of the Royal Astronomical Society

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The low surface brightness disc galaxy Malin 2 challenges the "standard" theory of galaxy evolution by its enormous total mass ∼ 2 · 10 12 M which must have been formed without recent major merger events. The aim of our work is to create a coherent picture of this exotic object by using the new optical multicolor photometric and spectroscopic observations at Apache Point Observatory as well as archival datasets from Gemini and wide-field surveys. We performed the Malin 2 mass modelling, estimated the contribution of the host dark halo and found that it had acquired its low central density ρ 0 0.003 M /pc 3 and the huge isothermal sphere core radius r c = 27.3 kpc before the disc subsystem was formed. Our spectroscopic data analysis reveals complex kinematics of stars and gas in the very inner region (r = 5 − 7 kpc). We measured the oxygen abundance in several clumps and concluded that the gas metallicity decreases from the solar value in the centre to a half of that at 20 − 30 kpc. We found a small satellite projected onto the galaxy disc at 14 kpc from the centre and measured its mass (1/500 of the host galaxy) and gas metallicity (similar to that of Malin 2 disc at the same distance). One of the unique properties of Malin 2 turned to be the apparent imbalance of the interstellar media: the molecular gas is in excess with respect to the atomic gas for given values of the gas equilibrium turbulent pressure. We explain this imbalance by the presence of a significant portion of the dark gas not observable in CO and the Hi 21-cm lines. We also show that the depletion time of the observed molecular gas traced by CO is nearly the same as in normal galaxies. Our modelling of the UV-to-optical spectral energy distribution favours the exponentially declined star formation history over a single-burst scenario. We argue that the massive and rarefied dark halo which had formed before the disc component well describes all the observed properties of Malin 2 and there is no need to assume additional "catastrophic" scenarios (such as a major merging) proposed previously to explain the origin of giant LSB galaxies.

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Relation Between BCDS and Blue LSBGS

Abstract: Two important questions are connected to the evolutionary history of blue compact dwarf galaxies (BCDs): the triggering mechanism of the starburst and the properties of the precursor(s) and successor. The halos of many BCDs show red colours indicating that the host… Show more

Cited by 20 publications

References 0 publications

Structure-dynamics relations for late-type spiral and dwarf irregular galaxies revisited

Structure-dynamics relations for late-type spiral and dwarf irregular galaxies revisited

The Puzzle of the Polar Structure in NGC 4650A

A portrait of Malin 2: a case study of a giant low surface brightness galaxy

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