25,723 research outputs found
Lick Indices In The Thin And Thick Disks Of Edge-On Disk Galaxies
No full textWe have measured Lick index equivalent widths to derive luminosity weighted stellar ages and metallicities for thin-and thick-disk-dominated regions of nine edge-on disk galaxies with the ARC 3.5 m telescope at Apache Point Observatory. In all cases, the thick disks are confirmed to be old stellar populations, with typical ages between 4 and 10 Gyr. The thin disks are uniformly younger than the thick disks, and show strong radial age gradients, with the outer regions of the disks being younger than 1 Gyr. We do not detect any significant metallicity differences or alpha-element enhancement in the thick-disk stars compared to the thin disk, due to the insensitivity of the Lick indices to these differences at low metallicity. We compare these results to thick disks measured in other systems and to predictions from thick-disk formation models.NSF CAREER AST 02-38683Alfred P. Sloan FoundationMcDonald Observator
The Kinematics Of Thick Disks In Nine External Galaxies
No full textWe present kinematic measurements of thin- and thick-disk components in a sample of nine edge-on galaxies. We extract stellar and ionized gas rotation curves at and above the galaxies' midplanes using the Ca II triplet absorption features and H alpha emission lines measured with the GMOS spectrographs on Gemini-North and Gemini-South. For the higher mass galaxies in the sample, we fail to detect differences between the thin- and thick-disk kinematics. In the lower mass galaxies, there is a wide range of thick-disk behavior, including thick disks with substantial lag and one counterrotating thick disk. We compare our rotation curves with expectations from thick-disk formation models and conclude that the wide variety of thick-disk kinematics favors a formation scenario in which thick-disk stars are accreted or formed during merger events as opposed to models that form thick disks through gradual thin- disk heating.NSF CAREER AST 02-38683Alfred P. Sloan FoundationAstronom
Author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
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A Panoply Of Cepheid Light Curve Templates
No full textWe have generated accurate V and I template light curves using a combination of Fourier decomposition and principal component analysis for a large sample of Cepheid light curves. Unlike previous studies, we include short-period Cepheids and stars pulsating in the first overtone mode in our analysis. Extensive Monte Carlo simulations show that our templates can be used to precisely measure Cepheid magnitudes and periods, even in cases where there are few observational epochs. These templates are ideal for characterizing serendipitously discovered Cepheids and can be used in conjunction with surveys such as Pan-Starrs and LSST where the observational sampling may not be optimized for Cepheids.Harlen J. Smith Post-doctoral FellowshipNSF AST-0238683Alfred P. Sloan FoundationNASA G0-10915, NAS5-26555Space Telescope Institute AR-10945Astronom
The ACS Nearby Galaxy Survey Treasury. III. Cepheids In The Outer Disk Of M81
No full textThe ACS Nearby Galaxy Survey Treasury (ANGST) has acquired deep ACS imaging of a field in the outer disk of the large spiral galaxy M81. These data were obtained over a total of 20 Hubble Space Telescope orbits, providing a baseline long enough to reliably identify Cepheid variable stars in the field. Fundamental mode and first overtone types have been distinguished through comparative fits with corresponding Cepheid light curve templates derived from principal component analysis of confirmed Cepheids in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Milky Way. A distance modulus of 27.78 +/- 0.05(r) +/- 0.14(s) with a corresponding distance of 3.60 +/- 0.23 Mpc has been calculated from a sample of 11 fundamental mode and two first overtone Cepheids (assuming an LMC distance modulus of mu(LMC) = 18.41 +/- 0.10(r) +/- 0.13(s)).NASA G0-10915, NAS5-26555Space Telescope Institute AR-10945Astronom
Moral Good, the Beatific Vision, and God’s Kingdom Writings by Germain Grisez and Peter Ryan, S.J.. Edited by Peter J. Weigel
No full textFor close to half a century, the work of Germain Grisez has been highly influential, and his writings continue to receive considerable attention from philosophers and theologians of diverse viewpoints. His co-author for this work is the professor and noted moral theologian Fr. Peter Ryan, S.J., currently the executive director of the Secretariat of Doctrine and Canonical Affairs of the United States Conference of Catholic Bishops (USCCB). These two eminent scholars explore fundamental questions about Christian eschatology, moral theory, the purpose of human life, and the promise of human fulfilment. The authors examine Christian teaching on the final destiny of persons, investigating the meaning of God's kingdom, the hope of the beatific vision, and the centrality of moral goodness and divine grace in one's final end. This work is an ideal source for students, scholars, ministers and lay persons interested in basic questions of Christian theology, the philosophy of religion, ethical theory, and Catholic doctrin
Murder on the mountain: author talk with Peter J. Wosh
No full textAuthor talk by Peter J. Wosh on May 5th, 2022, on his book, "Murder on the Mountain: crime, passion, and punishment in gilded age New Jersey.
lsst/rubin_scheduler: v1.1.1
No full text<p>V1.1.1</p>
<p>Primary updates:</p>
<ul>
<li>Addition of a jerk component to the KinematicModel. While this is disabled by default in this release (infinite jerk), it allows the option of adding a finite jerk to the kinematic model for evaluation of this effect.</li>
<li>Addition of documentation for the simulation archive code (which enables easier analysis of nightly simulations), and additional documentation for the rotator settings (please read, if creating your own FBS targets from the scheduler).</li>
<li>Added the option for SchemaConverter to append to an existing sqlite database, if desired.</li>
<li>Made it easier to run the ModelObservatory with subsets of 'ideal' conditions -- i.e. ideal cloud and no downtime, but not idealized seeing.</li>
<li>Cross-platform and rounding issues addressed in a couple of locations, by extension of IntRounded into new methods.</li>
<li>(optional) use of lsst.resources to load skybrightness files.</li>
<li>Code reconfiguration so that the optimal path calculation for a series of visits is a utility, not part of (a specific) Survey class.</li>
</ul>
<p>Some other notable updates:</p>
<ul>
<li>Update to purest 8 and black 24.</li>
<li>Fix code coverage tests in GitHub actions.</li>
<li>No more ruff failures!</li>
</ul>
<h2>What's Changed</h2>
<ul>
<li>tickets/PREOPS-4831: fix code coverage tests in github action by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/36</li>
<li>tickets/PREOPS-4775: Document the prototype sim archive by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/33</li>
<li>tickets/PREOPS-4736: Support loading of sky brightess with lsst.resources in rubin_scheduler by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/34</li>
<li>Tickets/opsim 1114 Add jerk to the telescope kinematic model by @yoachim in https://github.com/lsst/rubin_scheduler/pull/32</li>
<li>rotator documentation by @yoachim in https://github.com/lsst/rubin_scheduler/pull/35</li>
<li>tickets/PREOPS-4836: make conda package optional in rubin_scheduler by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/37</li>
<li>tickets/PREOPS-4846: update rubin_scheduler for pytest 8 and black 24 by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/38</li>
<li>IntRounded into TSP code by @yoachim in https://github.com/lsst/rubin_scheduler/pull/40</li>
<li>Fixing ruff issues by @yoachim in https://github.com/lsst/rubin_scheduler/pull/41</li>
<li>remove pytest-black dependency by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/39</li>
<li>Update ComCam by @yoachim in https://github.com/lsst/rubin_scheduler/pull/42</li>
<li>move path optimization out of survey object by @yoachim in https://github.com/lsst/rubin_scheduler/pull/43</li>
<li>easier to run model observatory with ideal conditions by @yoachim in https://github.com/lsst/rubin_scheduler/pull/44</li>
<li>let SchemaConverter append to an already existing sqlite file by @yoachim in https://github.com/lsst/rubin_scheduler/pull/45</li>
</ul>
<p><strong>Full Changelog</strong>: https://github.com/lsst/rubin_scheduler/compare/v1.1.0...v1.1.1</p>
lsst/rubin_scheduler: v1.1.0
No full text<p>Significant feature updates available in this release include :</p>
<ul>
<li>The ModelObservatory will run all the way to sunrise and sunset, extending the potential use of rubin_scheduler beyond -12 degree twilight.</li>
<li>The addition of altitude and azimuth limits to the Conditions object which passes incoming telemetry to the scheduler. This is coupled with an new mask basis function, AltAzShadowMaskBasisFunction which uses these limits set by the Conditions object, or optional tighter constraints set by kwargs, to mask off unavailable areas of the sky (as well as provides an optional 'shadow' to prevent early observations of the fields which would move into these unavailable regions). It is generally recommended to include the limits provided by the Conditions object into any Survey class configured by a user.</li>
<li>The addition of a PointingSurvey subclass, which is a slight generalization of a FieldSurvey but allows multiple (single field) targets within the same Survey class. There is additional documentation of the use of this new subclass in the rubin_sim_notebooks tutorials.</li>
<li>Additional support for schedview visualizations of the scheduler outputs, including the addition of an archive which can include S3 buckets to store simulation outputs (which can later be retrieved in schedview dashboards for visualization). NOTE that this now adds lsst-resources as an optional package. lsst-resources is necessary for use of the archive portion of the code.</li>
</ul>
<p>Bugfixes continue, as always.</p>
<ul>
<li>A bug introduced after v1.0.0 caused the near sun twilight micro survey to fail to execute continuously over the survey lifetime. We then fixed that bug. (note that no released version of rubin_scheduler included this bug).</li>
<li>We continue to strive for cross-platform repeatability, and updated IntRounded to enable this goal.</li>
<li>The DitherDetailer could occasionally push requested RA into negative values, but now wraps the RA values properly into 0-360 degrees.</li>
<li>We continue to work on updating and clarifying the documentation.</li>
</ul>
<p>The rubin_scheduler software is maintained primarily by the Rubin Survey Scheduling Team - @yoachim, @ehneilsen and @rhiannonlynne</p>
<h2>What's Changed</h2>
<ul>
<li>deprecate thomson and training dirs by @yoachim in https://github.com/lsst/rubin_scheduler/pull/13</li>
<li>OPSIM-893: bugfix/feature. Update IntRounded for cross-platform repeatability. by @yoachim in https://github.com/lsst/rubin_scheduler/pull/15</li>
<li>Documentation. Add initial rubin_scheduler overview page to documentation. by @rhiannonlynne in https://github.com/lsst/rubin_scheduler/pull/16</li>
<li>Feature. modelobservatory can run all the way to sunrise and set (not just -12deg twilight). by @yoachim in https://github.com/lsst/rubin_scheduler/pull/17</li>
<li>Documentation. Add drop-down for FBS scheduler pieces by @rhiannonlynne in https://github.com/lsst/rubin_scheduler/pull/18</li>
<li>OPSIM-1105: bugfix. Ensure twilight near-sun survey executes. by @yoachim in https://github.com/lsst/rubin_scheduler/pull/19</li>
<li>PREOPS-4646: feature- Support addition of opsim data to an archive for use by schedview-prenight by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/20</li>
<li>PREOPS-4776: bug fix - Fix import order for isort in rubin_scheduler by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/23</li>
<li>OPSIM-1104: feature. Add PointingSurvey subclass. by @yoachim in https://github.com/lsst/rubin_scheduler/pull/21</li>
<li>PREOPS-4779: bug fix - make sim_archive be robust toward presence of absence of trailing / by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/25</li>
<li>PREOPS-4781: feature - make save of scheduler pickle work for arbitrary paths, not just from the current dir. by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/27</li>
<li>PREOPS-4780: bug fix - fix end date of simulation to be closed interval, not open interval by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/26</li>
<li>PREOPS-4782: bug fix - when requesting time during the day, set available block size time to 0 by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/24</li>
<li>OPSIM-1112: feature - scripted surveys avoid the start of twilight by @yoachim in https://github.com/lsst/rubin_scheduler/pull/28</li>
<li>OPSIM-1111: feature - Add altitude and azimuth limits to Conditions, along with new basis function + shadow mask by @yoachim in https://github.com/lsst/rubin_scheduler/pull/22</li>
<li>PREOPS-4795: feature - Use SITCOMTN-32 dayObs defn. for rollover time in prenight sim archive by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/29</li>
<li>OPSIM-1113: bugfix for dither detailer (wrap RA) and DDF prescheduling for morning twilight by @yoachim in https://github.com/lsst/rubin_scheduler/pull/30</li>
<li>PREOPS-4828: feature - make lsst.resource dependency of rubin_scheduler optional by @ehneilsen in https://github.com/lsst/rubin_scheduler/pull/31</li>
</ul>
<p><strong>Full Changelog</strong>: https://github.com/lsst/rubin_scheduler/compare/v1.0.0...v1.1.0</p>
Lunchtime Talk with Author and Attorney Peter Godwin
No full textAuthor and attorney Peter Godwin gave a lunchtime talk about the topics discussed in his book, The Fear, which focuses on the human rights situation in Zimbabwe under the rule of Robert Mugabe
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