scholarly journals A tidal tale: detection of several stellar streams in the environment of NGC 1052

2019 ◽  
Vol 624 ◽  
pp. L6 ◽  
Author(s):  
Oliver Müller ◽  
R. Michael Rich ◽  
Javier Román ◽  
Mustafa K. Yıldız ◽  
Michal Bílek ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Dwarf Galaxy ◽  
Early Type ◽  
Tidal Interaction ◽  
Low Surface Brightness ◽  
Stellar Streams ◽  
Early Type Galaxy ◽  
Band Image

The possible existence of two dark-matter-free galaxies (NGC 1052-DF2 and NGC 1052-DF4) in the field of the early-type galaxy NGC 1052 presents a challenge to theories of dwarf galaxy formation according to the current cosmological paradigm. We carried out a search for signatures of past interactions connected to the putative hosts of NGC 1052-DF2 and NGC 1052-DF4 using a very deep L-band image obtained with the 0.7 m Jeanne Rich telescope that reach a surface brightness limit of 28.5 mag arcsec−2 in the r band. We found several low-surface brightness features, possibly consistent with an ongoing merger history in this group. We find a tidal interaction between NGC 1052 and NGC 1047, confirming a physical association. Furthermore, we find a stellar loop around NGC 1052 in the direction of NGC 1042 and a stellar stream pointing in the direction of NGC 1052-DF2, but they are not directly connected. We find no evidence for a recent tidal interaction for NGC 1052-DF2 and NGC 1052-DF4. No LSB features have been uncovered around the spiral galaxy NGC 1042, which leaves the association (physical or projected) between NGC 1052 and NGC 1042 ambiguous, although they have similar radial velocities. Their association will only be established when accurate distances to both objects have been measured.

scholarly journals Dark Matter and Galaxy Formation

1997 ◽  
Vol 14 (1) ◽  
pp. 4-7 ◽  
Author(s):  
K. C. Freeman
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Groups Of Galaxies ◽  
Normal Galaxies ◽  
Large Numbers ◽  
Sky Survey ◽  
Low Surface Brightness

AbstractIn addition to large numbers of normal galaxies, the multibeam HI Parkes all-sky survey will probably discover intergalactic HI clouds, very low-surface-brightness, gas-rich galaxies, and small HI clouds in nearby groups of galaxies. I will briefly discuss some aspects of why these classes of objects are interesting in the context of dark matter and galaxy formation.

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 A rare example of low surface-brightness radio lobes in a gas-rich early-type galaxy: the story of NGC 3998

2016 ◽  
Vol 592 ◽  
pp. A94 ◽  
Author(s):  
Bradley S. Frank ◽  
Raffaella Morganti ◽  
Tom Oosterloo ◽  
Kristina Nyland ◽  
Paolo Serra
Keyword(s):  
Surface Brightness ◽  
Early Type ◽  
Low Surface Brightness ◽  
Early Type Galaxy

A full pipeline for modelling low surface brightness galaxies

2019 ◽  
Vol 14 (S353) ◽  
pp. 279-280
Author(s):  
Marius Peper ◽  
Boudewijn F. Roukema ◽  
Krzysztof Bolejko
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Surface Brightness ◽  
Dark Matter Halo ◽  
Cosmological Simulations ◽  
Galaxy Formation And Evolution ◽  
Low Surface Brightness ◽  
Formation And Evolution ◽  
Low Surface Brightness Galaxies

AbstractCosmological simulations are a powerful tool to test various cosmological and galaxy formation scenarios. The discovery of low surface brightness objects has been a challenge for both of these fields. Our work aims to create a fully reproducible pipeline to generate a realistic dark matter halo catalog with corresponding information on galaxy formation and evolution.

scholarly journals The first detection of ultra-diffuse galaxies in the Hydra I cluster from the VEGAS survey

2020 ◽  
Vol 642 ◽  
pp. A48
Author(s):  
E. Iodice ◽  
M. Cantiello ◽  
M. Hilker ◽  
M. Rejkuba ◽  
M. Arnaboldi ◽  
...  
Keyword(s):  
Surface Brightness ◽  
Total Population ◽  
Matter Content ◽  
Early Type ◽  
Low Surface Brightness ◽  
Colour Distribution ◽  
Specific Frequency ◽  
Stellar Masses ◽  
Low Surface Brightness Galaxies ◽  
Early Type Galaxy

In this paper, we report the discovery of 27 low-surface brightness galaxies, of which 12 are candidates for ultra-diffuse galaxies (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey (VEGAS). This first sample of UDG candidates in the Hydra I cluster represents an important step in our project that aims to enlarge the number of confirmed UDGs and, through study of statistically relevant samples, constrain the nature and formation of UDGs. This study presents the main properties of this class of galaxies in the Hydra I cluster. For all UDGs, we analysed the light and colour distribution, and we provide a census of the globular cluster (GC) systems around them. Given the limitations of a reliable GC selection based on two relatively close optical bands only, we find that half of the UDG candidates have a total GC population consistent with zero. Of the other half, two galaxies have a total population larger than zero at 2σ level. We estimate the stellar mass, the total number of GCs, and the GC specific frequency (SN). Most of the candidates span a range of stellar masses of 107 − 108 M⊙. Based on the GC population of these newly discovered UDGs, we conclude that most of these galaxies have a standard or low dark matter content, with a halo mass of ≤1010 M⊙.

scholarly journals A distance of 13 Mpc resolves the claimed anomalies of the galaxy lacking dark matter

2019 ◽  
Vol 486 (1) ◽  
pp. 1192-1219 ◽  
Author(s):  
Ignacio Trujillo ◽  
Michael A Beasley ◽  
Alejandro Borlaff ◽  
Eleazar R Carrasco ◽  
Arianna Di Cintio ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galaxy Formation ◽  
Globular Clusters ◽  
Surface Brightness ◽  
Careful Analysis ◽  
Matter Content ◽  
Low Surface Brightness ◽  
Normal Distance ◽  
The Galaxy ◽  
The Uk

Abstract The claimed detection of a diffuse galaxy lacking dark matter represents a possible challenge to our understanding of the properties of these galaxies and galaxy formation in general. The galaxy, already identified in photographic plates taken in the summer of 1976 at the UK 48-in Schmidt telescope, presents normal distance-independent properties (e.g. colour, velocity dispersion of its globular clusters). However, distance-dependent quantities are at odds with those of other similar galaxies, namely the luminosity function and sizes of its globular clusters, mass-to-light ratio, and dark matter content. Here we carry out a careful analysis of all extant data and show that they consistently indicate a much shorter distance (13 Mpc) than previously indicated (20 Mpc). With this revised distance, the galaxy appears to be a rather ordinary low surface brightness galaxy (Re = 1.4 ± 0.1 kpc; M⋆ = 6.0 ± 3.6 × 107 M⊙) with plenty of room for dark matter (the fraction of dark matter inside the half-mass radius is >75 per cent and Mhalo/M⋆>20) corresponding to a minimum halo mass >109 M⊙. At 13 Mpc, the luminosity and structural properties of the globular clusters around the object are the same as those found in other galaxies.

scholarly journals A search for LSB dwarf galaxies in various environments

2004 ◽  
Vol 220 ◽  
pp. 341-342
Author(s):  
Sarah Roberts ◽  
Jonathan Davies ◽  
Sabina Sabatini
Keyword(s):  
Dark Matter ◽  
Hierarchical Clustering ◽  
Surface Brightness ◽  
Cold Dark Matter ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Low Surface Brightness ◽  
Galaxy Populations

The varying dwarf galaxy populations in different environments pose a problem for Cold Dark Matter (CDM) hierarchical clustering models. in this paper we present results from a survey conducted in different environments to search for low surface brightness (LSB) dwarf galaxies.

scholarly journals Hunting ghosts: the iconic stellar stream(s) around NGC 5907 under scrutiny

2019 ◽  
Vol 632 ◽  
pp. L13 ◽  
Author(s):  
Oliver Müller ◽  
Ana Vudragović ◽  
Michal Bílek
Keyword(s):  
Galaxy Formation ◽  
Surface Brightness ◽  
Double Loop ◽  
New Work ◽  
Low Surface Brightness ◽  
Stellar Streams ◽  
History Of ◽  
Independent Confirmation

Stellar streams are regarded as crucial objects for testing galaxy formation models because their morphology traces the underlying potentials and their occurrence tracks the assembly history of the galaxies. The existence of one of the most iconic stellar streams, the double loop around NGC 5907, has recently been questioned by new observations with the Dragonfly telescope. This new work only finds parts of the stream, even though a 1σ surface brightness limit of 30.3 mag arcsec−2 in the g band was reached. Using 7.2 h of luminance L-band imaging with the Milanković 1.4-m telescope, we have reobserved the putative double-loop part to confirm or reject this assessment. We do not find signs of the double loop, but see only a single knee-shaped stellar stream. Comparing our results to the data by the Dragonfly team, we find the same features. Our observations reach a 1σ surface brightness limit of 29.7 mag arcsec−2 in the g band. These findings emphasize the need for independent confirmation of detections of very low-surface brightness features.

scholarly journals NIHAO – XXV. Convergence in the cusp-core transformation of cold dark matter haloes at high star formation thresholds

2020 ◽  
Vol 499 (2) ◽  
pp. 2648-2661
Author(s):  
Aaron A Dutton ◽  
Tobias Buck ◽  
Andrea V Macciò ◽  
Keri L Dixon ◽  
Marvin Blank ◽  
...  
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Galaxy Formation ◽  
Cold Dark Matter ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Good Description ◽  
Good Match ◽  
Virial Mass ◽  
Density Threshold

ABSTRACT We use cosmological hydrodynamical galaxy formation simulations from the NIHAO project to investigate the response of cold dark matter (CDM) haloes to baryonic processes. Previous work has shown that the halo response is primarily a function of the ratio between galaxy stellar mass and total virial mass, and the density threshold above which gas is eligible to form stars, n[cm−3]. At low n all simulations in the literature agree that dwarf galaxy haloes are cuspy, but at high n ≳ 100 there is no consensus. We trace halo contraction in dwarf galaxies with n ≳ 100 reported in some previous simulations to insufficient spatial resolution. Provided the adopted star formation threshold is appropriate for the resolution of the simulation, we show that the halo response is remarkably stable for n ≳ 5, up to the highest star formation threshold that we test, n = 500. This free parameter can be calibrated using the observed clustering of young stars. Simulations with low thresholds n ≤ 1 predict clustering that is too weak, while simulations with high star formation thresholds n ≳ 5, are consistent with the observed clustering. Finally, we test the CDM predictions against the circular velocities of nearby dwarf galaxies. Low thresholds predict velocities that are too high, while simulations with n ∼ 10 provide a good match to the observations. We thus conclude that the CDM model provides a good description of the structure of galaxies on kpc scales provided the effects of baryons are properly captured.

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