Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where R. Brent Tully is active.

Publication


Featured researches published by R. Brent Tully.


The Astronomical Journal | 2009

THE EXTRAGALACTIC DISTANCE DATABASE

R. Brent Tully; Luca Rizzi; Edward J. Shaya; Helene M. Courtois; D. I. Makarov; Bradley A. Jacobs

A database can be accessed on the Web at http://edd.ifa.hawaii.edu that was developed to promote access to information related to galaxy distances. The database has three functional components. First, tables from many literature sources have been gathered and enhanced with links through a distinct galaxy naming convention. Second, comparisons of results both at the levels of parameters and of techniques have begun and are continuing, leading to increasing homogeneity and consistency of distance measurements. Third, new material is presented arising from ongoing observational programs at the University of Hawaii 2.2 m telescope, radio telescopes at Green Bank, Arecibo, and Parkes and with the Hubble Space Telescope. This new observational material is made available in tandem with related material drawn from archives and passed through common analysis pipelines.


The Astrophysical Journal | 2008

Our Peculiar Motion Away from the Local Void

R. Brent Tully; Edward J. Shaya; I. D. Karachentsev; Helene M. Courtois; Dale D. Kocevski; Luca Rizzi; Alan Campbell Peel

The peculiar velocity of the Local Group of galaxies manifested in the cosmic microwave background dipole is found to decompose into three dominant components. The three components are clearly separated because they arise on distinct spatial scales and are fortuitously almost orthogonal in their influences. The nearest, which is distinguished by a velocity discontinuity at ~7 Mpc, arises from the evacuation of the Local Void. We lie in the Local Sheet that bounds the void. Random motions within the Local Sheet are small, and we advocate a reference frame with respect to the Local Sheet in preference to the Local Group. Our Galaxy participates in the bulk motion of the Local Sheet away from the Local Void. The component of our motion on an intermediate scale is attributed to the Virgo Cluster and its surroundings, 17 Mpc away. The third and largest component is an attraction on scales larger than 3000 km s−1 and centered near the direction of the Centaurus Cluster. The amplitudes of the three components are 259, 185, and 455 km s−1, respectively, adding collectively to 631 km s−1 in the reference frame of the Local Sheet. Taking the nearby influences into account, particularly that of the Local Void, causes the residual attributed to large scales to align with observed concentrations of distant galaxies and reduces somewhat the amplitude of motion attributed to their pull. Concerning the motion of ~260 km s−1 away from the Local Void, given the velocities expected from gravitational instability theory in the standard cosmological paradigm, the distance to the center of the Local Void must be at least 23 Mpc from our position. The Local Void is extremely large.


The Astrophysical Journal | 2000

Distances to Galaxies from the Correlation between Luminosities and Line Widths. III. Cluster Template and Global Measurement of H0

R. Brent Tully; M. J. Pierce

The correlation between the luminosities and rotation velocities of galaxies can be used to estimate distances to late-type galaxies. It is an appropriate moment to reevaluate this method given the great deal of new information available. The major improvements described here include: (1) the template rela- tions can now be de—ned by large, complete samples, (2) the samples are drawn from a wide range of environments, (3) the relations are de—ned by photometric information at the B, R, I, and K@ bands, (4) the multiband information clari—es problems associated with internal reddening, (5) the template zero points are de—ned by 24 galaxies with accurately known distances, and (6) the relations are applied to 12 clusters scattered across the sky and out to velocities of 8000 km s~1. The biggest change from earlier calibrations are associated with point 5. Roughly a 15% increase in the distance scale has come about with the —vefold increase in the number of zero-point calibrators. The overall increase in the distance scale from the luminosityline width methodology is about 10% after consideration of all factors. Modulo an assumed distance to the Large Magellanic Cloud of 50 kpc and no metallicity corrections to the Cepheid calibration, the resulting value of the Hubble constant is km s~1 Mpc~1, H 0 \ 77 ^ 8 where the error is the 95% probable statistical error. Cumulative systematic errors internal to this analysis should not exceed 10%. Uncertainties in the distance scale ladder external to this analysis are estimated at D10%. If the Cepheid calibration is shifted from the LMC to NGC 4258 with a distance established by observations of circumnuclear masers, then is larger by 12%. H 0 Subject headings: distance scalegalaxies: distances and redshiftsgalaxies: fundamental parameters


The Astrophysical Journal | 2007

Tip of the Red Giant Branch Distances. II. Zero-Point Calibration

Luca Rizzi; R. Brent Tully; D. I. Makarov; L. N. Makarova; Andrew E. Dolphin; Shoko Sakai; Edward J. Shaya

The luminosity of the tip of the red giant branch (TRGB) provides an excellent measure of galaxy distances and is easily determined in the resolved images of nearby galaxies observed with Hubble Space Telescope. There is now a large amount of archival data that are relevant to the TRGB methodology and offer comparisons with other distance estimators. Zero-point issues related to the TRGB distance scale are reviewed in this paper. Consideration is given to the metallicity dependence of the TRGB, the transformations between HST flight systems and Johnson-Cousins photometry, the absolute magnitude scale based on horizontal branch measurements, and the effects of reddening. The zero point of the TRGB is established with a statistical accuracy of 1%, modulo the uncertainty in the magnitude of the horizontal branch, with a typical rms uncertainty of 3% in individual galaxy distances at high Galactic latitude. The zero point is consistent with the Cepheid period-luminosity relation scale but invites reconsideration of the claimed metallicity dependence with that method. The maser distance to NGC 4258 is consistent with TRGB but presently has lower accuracy.


The Astronomical Journal | 2013

Cosmicflows-2: The Data

R. Brent Tully; Helene M. Courtois; Andrew E. Dolphin; J. Richard Fisher; Philippe Héraudeau; Bradley A. Jacobs; I. D. Karachentsev; D. I. Makarov; L. N. Makarova; S. N. Mitronova; Luca Rizzi; Edward J. Shaya; Jenny G. Sorce; Po-Feng Wu

Cosmicflows-2 is a compilation of distances and peculiar velocities for over 8000 galaxies. Numerically the largest contributions come from the luminosity-line width correlation for spirals, the Tully-Fisher relation (TFR), and the related fundamental plane relation for E/S0 systems, but over 1000 distances are contributed by methods that provide more accurate individual distances: Cepheid, tip of the red giant branch (TRGB), surface brightness fluctuation, Type Ia supernova, and several miscellaneous but accurate procedures. Our collaboration is making important contributions to two of these inputs: TRGB and TFR. A large body of new distance material is presented. In addition, an effort is made to ensure that all the contributions, both our own and those from the literature, are on the same scale. Overall, the distances are found to be compatible with a Hubble constant H 0 = 74.4 ? 3.0?km?s?1?Mpc?1. The great interest going forward with this data set will be with velocity field studies. Cosmicflows-2 is characterized by a great density and high accuracy of distance measures locally, falling to sparse and coarse sampling extending to z = 0.1.


The Astrophysical Journal | 2002

Squelched Galaxies and Dark Halos

R. Brent Tully; Rachel S. Somerville; Neil Trentham; Marc Verheijen

There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be rising in rich clusters and flat in regions of low density. If galaxies form according to the model of hierarchical clustering, then there should be many small halos compared to the number of big halos. If this theory is valid, then there must be a mechanism that eliminates at least the visible component of galaxies in low-density regions. A plausible mechanism is photoionization of the intergalactic medium at a time before the epoch that most dwarf galaxies form in low-density regions but after the epoch of formation for similar systems that ultimately end up in rich clusters. The dynamical timescales are found to accommodate this hypothesis in a flat universe with Ωm 0.4. If small halos exist but simply cannot be located because they have never become the sites of significant star formation, they still might have dynamical manifestations. These manifestations are hard to identify in normal groups of galaxies because small halos do not make a significant contribution to the global mass budget. It could be entertained, however, that there are clusters of halos where there are only small systems, clusters that are at the low-mass end of the hierarchical tree. There may be places where only a few small galaxies managed to form, enough for us to identify and use as test probes of the potential. It turns out that such environments might be common. Four probable groups of dwarfs are identified within 5 Mpc, and the assumption that they are gravitationally bound suggests M/LB ~ 300-1200 M☉/L☉, a factor of 6 ± 2 times higher than typical values for groups with luminous galaxies.


Monthly Notices of the Royal Astronomical Society | 2002

The faint end of the galaxy luminosity function

Neil Trentham; R. Brent Tully

We present and discuss optical measurements of the faint end of the galaxy luminosity function down to M R = -10 in five different local environments of varying galaxy density and morphological content. The environments we studied, in order of decreasing galaxy density, are the Virgo Cluster, the NGC 1407 Group, the Coma I Group, the Leo Group and the NGC 1023 Group. Our results come from a deep wide-angle survey with the National Astronomical Observatories of Japan Subaru 8-m Telescope on Mauna Kea and are sensitive down to very faint surface-brightness levels. Galaxies were identified as group or cluster members on the basis of their surface brightness and morphology. The faintest galaxies in our sample have R ∼ 22.5. There were thousands of fainter galaxies but we cannot distinguish cluster members from background galaxies at these faint limits so do not attempt to determine a luminosity function fainter than M R = -10. In all cases, there are far fewer dwarfs than the numbers of low-mass haloes anticipated by cold dark matter theory. The mean logarithmic slope of the luminosity function between M R = -18 and M R = -10 is α ≃ -1.2, far shallower than the cold dark matter mass function slope of α ≃ -1.8. We would therefore need to be missing about 90 per cent of the dwarfs at the faint end of our sample in all the environments we study to achieve consistency with CDM theory. It is unlikely that such large numbers of dwarfs are missed because (i) the data are deep enough that we are sensitive to very low surface brightness galaxies, and (ii) the seeing is good enough that we can have some confidence in our ability to distinguish high surface brightness dwarfs from background galaxies brighter than R = 22.5. One caveat is that we miss compact members taken to be background galaxies, but such objects (like M32) are thought to be rare.


The Astronomical Journal | 2007

The Hubble Flow around the Centaurus A/M83 Galaxy Complex

I. D. Karachentsev; R. Brent Tully; Andrew E. Dolphin; M. E. Sharina; L. N. Makarova; D. I. Makarov; Shoko Sakai; Edward J. Shaya; Olga G. Kashibadze; V. E. Karachentseva; Luca Rizzi

We present Hubble Space Telescope ACS images and color-magnitude diagrams for 24 nearby galaxies in and near the constellation of Centaurus with radial velocities VLG < 550 km s-1. Distances are determined based on the luminosities of stars at the tip of the red giant branch that range from 3.0 to 6.5 Mpc. The galaxies are concentrated in two spatially separated groups around Cen A (NGC 5128) and M83 (NGC 5236). The Cen A group itself has a mean distance of 3.76 ± 0.05 Mpc, a velocity dispersion of 136 km s-1, a mean harmonic radius of 192 kpc, and an estimated orbital/virial mass of (6.4-8.1) × 1012 M⊙. This elliptical-dominated group is found to have a relatively high mass-to-light ratio: M/LB = 125 M⊙/L⊙. For the M83 group we derived a mean distance of 4.79 ± 0.10 Mpc, a velocity dispersion of 61 km s-1, a mean harmonic radius of 89 kpc, and an estimated orbital/virial mass of (0.8-0.9) × 1012 M⊙. This spiral-dominated group is found to have a relatively low M/LB = 34 M⊙/L⊙. The radius of the zero-velocity surface around Cen A lies at R0 = 1.40 ± 0.11 Mpc, implying a total mass within R0 of MT = (6.0 ± 1.4) × 1012 M⊙. This value is in good agreement with the Cen A orbital/virial mass estimates and provides confirmation of the relatively high M/LB of this elliptical-dominated group. The centroids of both groups, as well as surrounding field galaxies, have very small peculiar velocities, <25 km s-1, with respect to the local Hubble flow with H0 = 68 km s-1 Mpc-1.


The Astronomical Journal | 2006

Associations of Dwarf Galaxies

R. Brent Tully; Luca Rizzi; Andrew E. Dolphin; I. D. Karachentsev; V. E. Karachentseva; D. I. Makarov; L. N. Makarova; Shoko Sakai; Edward J. Shaya

The Hubble Space Telescope Advanced Camera for Surveys has been used to determine accurate distances for 20 galaxies from measurements of the luminosity of the brightest red giant branch stars. Five associations of dwarf galaxies that had originally been identified based on strong correlations on the plane of the sky and in velocity are shown to be equally well correlated in distance. Two more associations with similar properties have been discovered. Another association is identified that is suggested to be unbound through tidal disruption. The associations have the spatial and kinematic properties expected of bound structures with ? 1011 M?. However, these entities have little light, with the consequence that the mass-to-light ratios are in the range 100-1000 M? L. Within a well-surveyed volume extending to a 3 Mpc radius, all but one known galaxy lie within one of the groups or associations that have been identified.


The Astrophysical Journal | 2002

A Systematic X-Ray Search for Clusters of Galaxies behind the Milky Way

Harald Ebeling; Christopher Robinson Mullis; R. Brent Tully

We report on the design and status of the Clusters in the Zone of Avoidance (CIZA) project, the first systematic X-ray search for clusters of galaxies behind the Milky Way. We demonstrate that an X-ray survey can find galaxy clusters at low Galactic latitude where optical searches are inefficient because of massive obscuration and extinction problems. We discuss the rationale for such a survey in the context of large-scale structure studies and describe in detail the combined X-ray/optical/NIR approach used by CIZA to identify clusters of galaxies at |b| < 20?, a region of the sky that has traditionally been excluded from earlier cluster catalogs. So far, CIZA has identified and spectroscopically confirmed 137 galaxy clusters in what used to be the zone of avoidance; additional clusters have been confirmed in imaging observations and await spectroscopic observation. We present a catalog of the 73 X-ray-brightest CIZA clusters, 53 (73%) of which are new discoveries. This sample is statistically complete out to at least z ~ 0.075 (cz ~ 22,500 km s-1). We reassess local large-scale structure in the Great Attractor (GA) region in light of this first X-ray-selected cluster sample at low Galactic latitude. Our survey discovered CIZA J1324.7-5736, a luminous cluster at l = 3074, b = 50, cz = 5700 km s-1, and possibly as massive as A3627, but ruled out a hypothesized X-ray-luminous cluster around the radio galaxy PKS 1343-601. We argue that this region of the GA may be best described as a wall-like, triangular structure with CIZA J1324.7-5736, A3627, and the Centaurus Cluster (A3526) at its vertices. Our survey also discovered what could be a supercluster in the same region but at cz ~ 15,000 km s-1, i.e., behind the GA. We speculate that the latter system may be partly responsible for the large-scale flow observed in this direction out to about that distance.

Collaboration


Dive into the R. Brent Tully's collaboration.

Top Co-Authors

Avatar

I. D. Karachentsev

Russian Academy of Sciences

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Yehuda Hoffman

Hebrew University of Jerusalem

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

D. I. Makarov

Special Astrophysical Observatory

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge