Faint Photometry of Edge-On Spiral Galaxies: A Search for Massive Halos

1987 ◽  
pp. 425-425
Author(s):  
Michael F. Skrutskie ◽  
Mark A. Shure ◽  
Steven Beckwith
Keyword(s):  
Spiral Galaxies ◽  
Massive Halos

scholarly journals Faint Photometry of Edge-on Spiral Galaxies: A Search for Massive Halos

1987 ◽  
Vol 117 ◽  
pp. 425-425
Author(s):  
Michael F. Skrutskie ◽  
Mark A. Shure ◽  
Steven Beckwith
Keyword(s):  
Spiral Galaxies ◽  
Hydrogen Burning ◽  
Dwarf Stars ◽  
Color Changes ◽  
Upper Limits ◽  
Massive Halos ◽  
Halo Masses ◽  
Stellar Masses ◽  
M Dwarf Stars ◽  
Lower Limits

Upper limits have been set to the luminosity from the massive halos of three late-type edge-on spiral galaxies: NGC 2683 (Sb), NGC 4244 (Scd), and NGC 5907 (Sc). The limits resulted from simultaneous photometry in the visual (V) and 2.2μm (K) photometric bands which is sensitive to both luminosity and color changes along the minor axes of the three galaxies. The 3σ lower limits to the mass-to-light ratios for the halo of NGC 5907 are the largest ever recorded: M/Lv > 2000 and M/Lk > 64 in solar units. Since K band M/L for M-dwarf stars lying just above the hydrogen-burning limit is about 35, the results virtually eliminate the possibility that hydrogen-burning stars comprise more than a fraction of the halo masses. If the halos contain a more realistic spectrum of stellar masses, for example Population II, the visual band measurements imply that these stars account for less than one percent of the halo mass. Similar limits were obtained for NGC 4244 and NGC 2683. Variations of the V-K colors along and perpendicular to the disks show no sign of population changes toward redder objects at large galactocentric radii.

scholarly journals Mass-to-Light Ratios of Spiral Galaxies

1987 ◽  
Vol 117 ◽  
pp. 138-138
Author(s):  
J. Patricia Vader
Keyword(s):  
Theoretical Model ◽  
Spiral Galaxies ◽  
Evolution Of Galaxies ◽  
Large Structures ◽  
Model Predictions ◽  
Formation And Evolution ◽  
Color Bias ◽  
Massive Halos ◽  
Stellar Masses ◽  
The Universe

Mass-to-light ratios M/LH−0.5 and M/LB are plotted against color B-H−0.5 in Fig. 1 for 82 nearby spirals from the catalog of Aaronson et al. (1982, Ap. J. Suppl. 50, 241), with BT magnitudes from the RC2, |b| > 20°, 45° ≤ i ≤ 80°, and HI mass estimates. Total masses and infrared H−0.5 magnitudes are measured within the blue isophotal radii R25 and R25/3 respectively, which depend on galaxy color. This color bias is corrected for by replacing R25 by R'25, the radius a galaxy would have at a standard color B-H−0.5 = 2.17. Stellar masses M* and LHC luminosities within R'25 are obtained by substracting twice the HI mass and by extrapolation, respectively. Corrected ratios M*/LHC and M*/LB versus corrected color B-HC are shown in Fig. 1 together with theoretical model predictions. The corrected observed ratios are systematically larger for bluer galaxies than predicted so that bluer spirals seem to have relatively more massive halos, in agreement with earlier results (Tinsley, B.M. 1981 M.N.R.A.S. 194, 63; Vader, J. P. 1984, in Formation and Evolution of Galaxies and Large Structures in the Universe, eds. J. Audouze and J. T. Thanh Van, p. 227).

The massive halos of spiral galaxies

1994 ◽  
Vol 435 ◽  
pp. 599 ◽  
Author(s):  
Dennis Zaritsky ◽  
Simon D. M. White
Keyword(s):  
Spiral Galaxies ◽  
Massive Halos

scholarly journals Redshift Asymmetries and the Missing Mass

1987 ◽  
Vol 124 ◽  
pp. 503-506
Author(s):  
Gene G. Byrd ◽  
Mauri J. Valtonen
Keyword(s):  
Spiral Galaxies ◽  
Elliptical Galaxies ◽  
Coma Cluster ◽  
Missing Mass ◽  
Cluster Of Galaxies ◽  
Or Groups ◽  
Other Information ◽  
Massive Halos ◽  
The Universe ◽  
Very High

We study the existence of missing mass in the outermost regions of galaxies not accessible to study by rotation curve methods. We consider binary galaxies, groups and clusters of galaxies. Arp has previously explained redshift asymmetries in pairs or groups with “non-Doppler redshifts”. Instead, we propose the asymmetries indicate contamination by optical pairs or by members which are not gravitationally bound to the group or pair. The group samples which are commonly used to justify very high missing mass values in spiral galaxies (>> the mass detected by rotation curves) also exhibit significant redshift asymmetries. From this and other information, we conclude that spiral galaxies do not possess very massive halos. Only the rare giant elliptical galaxies, such as the binary pair in the center of the Coma Cluster of galaxies, apparently possess extremely massive halos. Dynamical effects of such giants lead to overestimates of the mass of clusters. The evidence indicates that missing mass sufficient to close the universe is not concentrated in individual galaxies, groups or rich clusters.

Faint photometry of edge-on spiral galaxies - A search for massive halos

1985 ◽  
Vol 299 ◽  
pp. 303 ◽  
Author(s):  
M. F. Skrutskie ◽  
M. A. Shure ◽  
S. Beckwith
Keyword(s):  
Spiral Galaxies ◽  
Massive Halos

scholarly journals Galaxy spin direction distribution in HST and SDSS show similar large-scale asymmetry

2020 ◽  
Vol 37 ◽  
Author(s):  
Lior Shamir
Keyword(s):  
Large Scale ◽  
Spiral Galaxies ◽  
Hubble Space Telescope ◽  
Gravitational Interaction ◽  
Large Data ◽  
Sloan Digital Sky Survey ◽  
Data Sets ◽  
Dipole Axis ◽  
Data Set ◽  
The Asymmetry

Abstract Several recent observations using large data sets of galaxies showed non-random distribution of the spin directions of spiral galaxies, even when the galaxies are too far from each other to have gravitational interaction. Here, a data set of $\sim8.7\cdot10^3$ spiral galaxies imaged by Hubble Space Telescope (HST) is used to test and profile a possible asymmetry between galaxy spin directions. The asymmetry between galaxies with opposite spin directions is compared to the asymmetry of galaxies from the Sloan Digital Sky Survey. The two data sets contain different galaxies at different redshift ranges, and each data set was annotated using a different annotation method. The results show that both data sets show a similar asymmetry in the COSMOS field, which is covered by both telescopes. Fitting the asymmetry of the galaxies to cosine dependence shows a dipole axis with probabilities of $\sim2.8\sigma$ and $\sim7.38\sigma$ in HST and SDSS, respectively. The most likely dipole axis identified in the HST galaxies is at $(\alpha=78^{\rm o},\delta=47^{\rm o})$ and is well within the $1\sigma$ error range compared to the location of the most likely dipole axis in the SDSS galaxies with $z>0.15$ , identified at $(\alpha=71^{\rm o},\delta=61^{\rm o})$ .

The co-responsibility of mass and environment in the formation of lenticular galaxies

2020 ◽  
Vol 15 (S359) ◽  
pp. 173-174
Author(s):  
A. Cortesi ◽  
L. Coccato ◽  
M. L. Buzzo ◽  
K. Menéndez-Delmestre ◽  
T. Goncalves ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Maximum Likelihood Method ◽  
Spiral Galaxies ◽  
Galactic Nuclei ◽  
Rotation Velocity ◽  
Elliptical Galaxies ◽  
Likelihood Method ◽  
Data Set ◽  
Lenticular Galaxies ◽  
Galaxies Kinematics

AbstractWe present the latest data release of the Planetary Nebulae Spectrograph Survey (PNS) of ten lenticular galaxies and two spiral galaxies. With this data set we are able to recover the galaxies’ kinematics out to several effective radii. We use a maximum likelihood method to decompose the disk and spheroid kinematics and we compare it with the kinematics of spiral and elliptical galaxies. We build the Tully- Fisher (TF) relation for these galaxies and we compare with data from the literature and simulations. We find that the disks of lenticular galaxies are hotter than the disks of spiral galaxies at low redshifts, but still dominated by rotation velocity. The mechanism responsible for the formation of these lenticular galaxies is neither major mergers, nor a gentle quenching driven by stripping or Active Galactic Nuclei (AGN) feedback.

scholarly journals Cosmic-Ray Driven Outflows to Mpc Scales from L* Galaxies

2020 ◽  
Author(s):  
Philip F Hopkins ◽  
T K Chan ◽  
Suoqing Ji ◽  
Cameron B Hummels ◽  
Dušan Kereš ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Plane Layer ◽  
Equilibrium Density ◽  
Pressure Gradients ◽  
Low Velocity ◽  
Star Forming ◽  
Stellar Feedback ◽  
Massive Halos ◽  
Halo Masses

Abstract We study the effects of cosmic rays (CRs) on outflows from star-forming galaxies in the circum and inter-galactic medium (CGM/IGM), in high-resolution, fully-cosmological FIRE-2 simulations (accounting for mechanical and radiative stellar feedback, magnetic fields, anisotropic conduction/viscosity/CR diffusion and streaming, and CR losses). We showed previously that massive (Mhalo ≳ 1011 M⊙), low-redshift (z ≲ 1 − 2) halos can have CR pressure dominate over thermal CGM pressure and balance gravity, giving rise to a cooler CGM with an equilibrium density profile. This dramatically alters outflows. Absent CRs, high gas thermal pressure in massive halos “traps” galactic outflows near the disk, so they recycle. With CRs injected in supernovae as modeled here, the low-pressure halo allows “escape” and CR pressure gradients continuously accelerate this material well into the IGM in “fast” outflows, while lower-density gas at large radii is accelerated in-situ into “slow” outflows that extend to >Mpc scales. CGM/IGM outflow morphologies are radically altered: they become mostly volume-filling (with inflow in a thin mid-plane layer) and coherently biconical from the disk to >Mpc. The CR-driven outflows are primarily cool (T ∼ 105 K) and low-velocity. All of these effects weaken and eventually vanish at lower halo masses (≲ 1011 M⊙) or higher redshifts (z ≳ 1 − 2), reflecting the ratio of CR to thermal+gravitational pressure in the outer halo. We present a simple analytic model which explains all of the above phenomena. We caution that these predictions may depend on uncertain CR transport physics.

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