J. L. Tonry

Publications (11)0 Total impact

• Source

  Available from: arxiv.org

  Article: Comparing the SBF Survey Velocity Field with the Gravity Field from Redshift Surveys

  J. P. Blakeslee, M Davis, J. L. Tonry, E. A. Ajhar, A. Dressler
  [show abstract] [hide abstract]
  ABSTRACT: We compare the predicted local peculiar velocity field from the IRAS 1.2 Jy flux-limited redshift survey and the Optical Redshift Survey (ORS) to the measured peculiar velocities from the recently completed SBF Survey of Galaxy Distances. The analysis produces a value of \beta = \Omega^{0.6}/b for the redshift surveys, where b is the linear biasing factor, and a tie to the Hubble flow, i.e., a value of H_0, for the SBF Survey. There is covariance between these parameters, but we find good fits with H_0 \approx 74 \kmsM for the SBF distances, \beta_I \approx 0.44 for the IRAS survey predictions, and \beta_O \approx 0.3 for the ORS. The small-scale velocity error \sigv \sim 200 \kms is similar to, though slightly larger than, the value obtained in our parametric flow modeling with SBF.
  11/1999;
• Source

  Available from: arxiv.org

  Article: A First Comparison of the SBF Survey Distances with the Galaxy Density Field: Implications for H_0 and Omega

  J. P. Blakeslee, M Davis, J. L. Tonry, A. Dressler, E. A. Ajhar
  [show abstract] [hide abstract]
  ABSTRACT: We compare the peculiar velocities measured in the SBF Survey of Galaxy Distances with the predictions from the density fields of the IRAS 1.2 Jy flux-limited redshift survey and the Optical Redshift Survey (ORS) to derive simultaneous constraints on the Hubble constant $H_0$ and the density parameter $\beta = \Omega^{0.6}/b$, where $b$ is the linear bias. We find $\beta_I=0.42^{+0.10}_{-0.06}$ and $\beta_O=0.26\pm0.08$ for the IRAS and ORS comparisons, respectively, and $H_0=74\pm4$ \kmsMpc (with an additional 9% uncertainty due to the Cepheids themselves). The match between predicted and observed peculiar velocities is good for these values of $H_0$ and $\beta$, and although there is covariance between the two parameters, our results clearly point toward low-density cosmologies. Thus, the unresolved discrepancy between the ``velocity-velocity'' and ``density-density'' measurements of $\beta$ continues. Comment: 4 pages with 3 embedded ps figures; uses emulateapj.sty (included). Accepted for publication in ApJ Letters
  10/1999;
• Source

  Available from: ArXiv

  Article: DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. IV. Variables in the Field M31D

  J. Kaluzny, B. J. Mochejska, K. Z. Stanek, M. Krockenberger, D. D. Sasselov, J. L. Tonry, M. Mateo
  [show abstract] [hide abstract]
  ABSTRACT: We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33 -- using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries, the distance estimates will be free of any intermediate steps. As a first step in the DIRECT project, between September 1996 and October 1997 we obtained 95 full/partial nights on the F. L. Whipple Observatory 1.2 m telescope and 36 full nights on the Michigan-Dartmouth-MIT 1.3 m telescope to search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper, fourth in the series, we present the catalog of variable stars, most of them newly detected, found in the field M31D $[(\alpha,\delta)= (11.\arcdeg03, 41.\arcdeg27), J2000.0]$. We have found 71 variable stars: 5 eclipsing binaries, 38 Cepheids and 28 other periodic, possible long period or non-periodic variables. The catalog of variables, as well as their photometry and finding charts, is available via anonymous ftp and the World Wide Web. The complete set of the CCD frames is available upon request. Comment: submitted to the Astronomical Journal, 30 pages, 20 figures; paper and data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/DIRECT/ and through WWW at http://cfa-www.harvard.edu/~kstanek/DIRECT/
  02/1999;
• Source

  Available from: arxiv.org

  Article: DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. III. Variables in the Field M31C

  K. Z. Stanek, J. Kaluzny, M. Krockenberger, D. D. Sasselov, J. L. Tonry, M. Mateo
  [show abstract] [hide abstract]
  ABSTRACT: We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33 -- using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, DEBs provide us with the potential to determine these distances with an accuracy better than 5%. The extensive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries, the distance estimates will be free of any intermediate steps. As a first step in the DIRECT project, between September 1996 and October 1997 we obtained 95 full/partial nights on the F. L. Whipple Observatory 1.2 m telescope and 36 full nights on the Michigan-Dartmouth-MIT 1.3 m telescope to search for DEBs and new Cepheids in the M31 and M33 galaxies. In this paper, third in the series, we present the catalog of variable stars, most of them newly detected, found in the field M31C [(alpha,delta)=(11.10, 41.42) deg, J2000.0}]. We have found 115 variable stars: 12 eclipsing binaries, 35 Cepheids and 68 other periodic, possible long period or non-periodic variables. The catalog of variables, as well as their photometry and finding charts, is available via anonymous ftp and the World Wide Web. The complete set of the CCD frames is available upon request. Comment: submitted to the Astronomical Journal, 39 pages, 27 figures; paper and data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/DIRECT/ and through WWW at http://cfa-www.harvard.edu/~kstanek/DIRECT/
  01/1999;
• Source

  Available from: arxiv.org

  Article: DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. II. Variables in the Field M31A

  K. Z. Stanek, J. Kaluzny, M. Krockenberger, D. D. Sasselov, J. L. Tonry, M. Mateo
  [show abstract] [hide abstract]
  ABSTRACT: We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33, using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, detached eclipsing binaries provide us with the potential to determine these distances with an accuracy better than 5%. The massive photometry obtained in order to detect DEBs provides us with the light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries the distance estimates will be free of any intermediate steps. As a first step of the DIRECT project, between September 1996 and January 1997 we have obtained 36 full nights on the Michigan-Dartmouth-MIT (MDM) 1.3-meter telescope and 45 full/partial nights on the F. L. Whipple Observatory (FLWO) 1.2-meter telescope to search for detached eclipsing binaries and new Cepheids in the M31 and the M33 galaxies. In this paper, second in the series, we present the catalog of variable stars, most of them newly detected, found in the field M31A ($\alpha_{2000.0},\delta_{2000}=11.34\deg,41.73\deg$). We have found 75 variable stars: 15 eclipsing binaries, 43 Cepheids and 17 other periodic, possible long period or non-periodic variables. The catalog of variables, as well as their photometry and finding charts, are available using the anonymous ftp service and the WWW. The CCD frames are available on request. Comment: submitted to the Astronomical Journal, 29 pages, 18 figures; paper and data available at ftp://cfa-ftp.harvard.edu/pub/kstanek/DIRECT/papers/M31A/ and through WWW at http://cfa-www.harvard.edu/~kstanek/DIRECT/
  12/1997;
• Article: DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. IV. Cepheids in M31 and M33

  D. D. Sasselov, M. Krockenberger, K. Z. Stanek, J. Kaluzny, J. L. Tonry, M. Mateo
  [show abstract] [hide abstract]
  ABSTRACT: During 1996 and 1997 we have obtained 95 nights on the FLWO 1.2-meter telescope and 35 nights on the MDM 1.3-meter telescope to search for detached eclipsing binaries and Cepheids in the M31 and the M33 galaxies. This is a first step in the ongoing program to improve the direct distance estimate to two important galaxies in the cosmological distance ladder -- M31 and M33. Detached eclipsing binaries provide us with the potential to determine these distances with an accuracy better than 5% and possibly to better than 1%. The massive photometry provides us with good light curves for known and new Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. With both Cepheids and eclipsing binaries the distance estimates will be free of any intermediate steps. We present the lightcurves of the Cepheids found in M31 and M33 and discuss the period-luminosity relations derived in different regions of the disk. We study the effects of differential extinction and metallicity, as well as the distribution of Cepheids in different spiral arms.
  11/1997; 29:1242.
• Source

  Available from: ArXiv

  Article: DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. I. Variables in the Field M31B

  J. Kaluzny, K. Z. Stanek, M. Krockenberger, D. D. Sasselov, J. L. Tonry, M. Mateo
  [show abstract] [hide abstract]
  ABSTRACT: We undertook a long term project, DIRECT, to obtain the direct distances to two important galaxies in the cosmological distance ladder -- M31 and M33, using detached eclipsing binaries (DEBs) and Cepheids. While rare and difficult to detect, detached eclipsing binaries provide us with the potential to determine these distances with an accuracy better than 5%. The massive photometry obtained in order to detect DEBs provides us with good light curves for the Cepheid variables. These are essential to the parallel project to derive direct Baade-Wesselink distances to Cepheids in M31 and M33. For both Cepheids and eclipsing binaries the distance estimates will be free of any intermediate steps. As a first step of the DIRECT project, between September 1996 and January 1997 we have obtained 36 full nights on the Michigan-Dartmouth-MIT (MDM) 1.3-meter telescope and 45 full/partial nights on the F. L. Whipple Observatory (FLWO) 1.2-meter telescope to search for detached eclipsing binaries and new Cepheids in the M31 and the M33 galaxies. In this paper, first in the series, we present the catalog of variable stars, most of them newly detected, found in the field M31B ($\alpha_{2000.0},\delta_{2000}=11.20\deg,41.59\deg$). We have found 85 variable stars: 12 eclipsing binaries, 38 Cepheids and 35 other periodic, possible long period or non-periodic variables. The catalog of variables, as well as their photometry and finding charts, are available using the anonymous ftp service and the WWW.
  04/1997;
• Source

  Available from: Andreas O. Jaunsen

  Article: The Quadruple Gravitational Lens PG1115+080: Time Delays and Models

  P. L. Schechter, C. D. Bailyn, R. Barr, R. Barvainis, C. M. Becker, G. M. Bernstein, J. P. Blakeslee, S. J. Bus, A. Dressler, E. E. Falco, [......], A. O. Jaunsen, M. Mateo, D. Mehlert, D. O. Richstone, L. S. Sparke, J. R. Thorstensen, J. L. Tonry, G. Wegner, D. W. Willmarth, G. Worthey
  [show abstract] [hide abstract]
  ABSTRACT: Optical photometry is presented for the quadruple gravitational lens PG1115+080. A preliminary reduction of data taken from November 1995 to June 1996 gives component ``C'' leading component ``B'' by 23.7+/-3.4 days and components ``A1'' and ``A2'' by 9.4 days. A range of models has been fit to the image positions, none of which gives an adequate fit. The best fitting and most physically plausible of these, taking the lensing galaxy and the associated group of galaxies to be singular isothermal spheres, gives a Hubble constant of 42 km/s/Mpc for Omega=1, with an observational uncertainty of 14%, as computed from the B-C time delay measurement. Taking the lensing galaxy to have an approximately E5 isothermal mass distribution yields H0=64 km/sec/Mpc while taking the galaxy to be a point mass gives H0=84 km/sec/Mpc. The former gives a particularly bad fit to the position of the lensing galaxy, while the latter is inconsistent with measurements of nearby galaxy rotation curves. Constraints on these and other possible models are expected to improve with planned HST observations.
  12/1996;
• Source

  Available from: articles.adsabs.harvard.edu

  Article: The SBF Survey: First Results on Large-Scale Flows

  J. L. Tonry, A. Dressler, J. P. Blakeslee, E. A. Ajhar
  201:70.
• Article: Constraining the Cosmic Mass Density from the SBF Survey Peculiar Velocities

  J. P. Blakeslee, J. L. Tonry, A. Dressler, E. A. Ajhar, M. Davis, J. A. Willick, M. A. Strauss, V. K. Narayan
  [show abstract] [hide abstract]
  ABSTRACT: The recently completed I-band Surface Brightness Fluctuations (SBF) Survey of Galaxy Distances includes high-quality distance measurements to nearly 300 early-type galaxies within 4000 km/s. We compare the peculiar velocities observed in this survey with those predicted from the galaxy density field found in flux-limited redshift surveys. Using linear gravitational instability theory and the IRAS flux-limited redshift survey, we constrain the parameter β = Ω0.6/b, where b is the linear biasing factor of the galaxies, to be β = 0.44 ± 0.08. The analysis also produces a value for the thermal velocity dispersion of the non-cluster galaxies in this sample, which we find to be about 180 km/s, and for the peculiar motion of about 150 km/s of the Local Group with respect to the mean local velocity field. We have also explored nonlinear gravitational models, which allow for independent constraints on Ω and the galaxy bias on scales of ~300 km/s. We discuss the latest results from this analysis.
  Proceedings of the International Astronomical Union 201:439.
• Article: ACS Virgo Cluster Survey. II. (Jordan+, 2004)

  A. Jordan, J. P. Blakeslee, E. W. Peng, S. Mei, P. Cote, L. Ferrarese, J. L. Tonry, D. Merritt, M. Milosavljevic, M. J. West
  [show abstract] [hide abstract]
  ABSTRACT: The ACS Virgo Cluster Survey is a large program to carry out multicolor imaging of 100 early-type members of the Virgo Cluster using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. Deep F475W and F850LP images (~SDSS g and z) are being used to study the central regions of the program galaxies, their globular cluster systems, and the three-dimensional structure of Virgo itself. In this paper, we describe in detail the data reduction procedures used for the survey, including image registration, drizzling strategies, the computation of weight images, object detection, the identification of globular cluster candidates, and the measurement of their photometric and structural parameters. (1 data file).