21 |
Isolated elliptical galaxiesReda, Fatma M. January 2007 (has links)
Thesis (Ph.D) - Swinburne University of Technology, Faculty of Information & Communication Technologies, 2007. / A thesis presented in fulfillment of the requirements of Doctor of Philosophy, Faculty of Information and Communication Technologies, Swinburne University of Technology, 2007. Typescript. Bibliography p. 109-118.
|
22 |
Thick disks in external galaxies /Yoachim, Peter, January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 177-196).
|
23 |
Supernova feedback in smoothed particle hydrodynamics simulations of galaxy formation /Stinson, Gregory, January 2007 (has links)
Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 137-151).
|
24 |
Structure of distant disk galaxies /Tamm, Antti. January 2006 (has links) (PDF)
Thesis (doctoral)--Tartu University, 2006. / Includes bibliographical references (54-61).
|
25 |
Could merged massive stellar clusters build up a dwarf galaxy ? /Fellhauer, Michael. January 2001 (has links)
Dissertation--University of Heidelberg, 2001. / Résumé en anglais et allemand. Bibliogr. p. 107-110.
|
26 |
Cospatial Star Formation and Supermassive Black Hole Growth in z ∼ 3 Galaxies: Evidence for In Situ Co-evolutionRujopakarn, W., Nyland, K., Rieke, G. H., Barro, G., Elbaz, D., Ivison, R. J., Jagannathan, P., Silverman, J. D., Smolčić, V., Wang, T. 07 February 2018 (has links)
We present a sub-kiloparsec localization of the sites of supermassive black hole (SMBH) growth in three active galactic nuclei (AGNs) at z similar to 3 in relation to the regions of intense star formation in their hosts. These AGNs are selected from Karl G. Jansky Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA) observations in the Hubble Ultra-Deep Field and COSMOS, with the centimetric radio emission tracing both star formation and AGN, and the sub/millimeter emission by dust tracing nearly pure star formation. We require radio emission to be >= 5 x more luminous than the level associated with the sub/millimeter star formation to ensure that the radio emission is AGN-dominated, thereby allowing localization of the AGN and star formation independently. In all three galaxies, the AGNs are located within the compact regions of gas-rich, heavily obscured, intense nuclear star formation, with R-e = 0.4-1.1 kpc and average star formation rates of similar or equal to 100-1200 M(circle dot)yr(-1). If the current episode of star formation continues at such a rate over the stellar mass doubling time of their hosts, similar or equal to 0.2 Gyr, the newly formed stellar mass will be of the order of 10(11)M(circle dot). within the central kiloparsec region, concurrently and cospatially with significant growth of the SMBH. This is consistent with a picture of in situ galactic bulge and SMBH formation. This work demonstrates the unique complementarity of VLA and ALMA observations to unambiguously pinpoint the locations of AGNs and star formation down to similar or equal to 30 mas, corresponding to; 230 pc at z = 3.
|
27 |
Massive Quenched Galaxies at z ∼ 0.7 Retain Large Molecular Gas ReservoirsSuess, Katherine A., Bezanson, Rachel, Spilker, Justin S., Kriek, Mariska, Greene, Jenny E., Feldmann, Robert, Hunt, Qiana, Narayanan, Desika 01 September 2017 (has links)
The physical mechanisms that quench star formation, turning blue star-forming galaxies into red quiescent galaxies, remain unclear. In this Letter, we investigate the role of gas supply in suppressing star formation by studying the molecular gas content of post-starburst galaxies. Leveraging the wide area of the Sloan Digital Sky Survey, we identify a sample of massive intermediate-redshift galaxies that have just ended their primary epoch of star formation. We present Atacama Large Millimeter/submillimeter Array CO(2-1) observations of two of these post-starburst galaxies at z similar to 0.7 with M-* similar to 2 10(11) M-circle dot. Their molecular gas reservoirs of (6.4 +/- 0.8) x 10(9) M-circle dot and (34.0 +/- 1.6) x 10(9) M-circle dot are an order of magnitude larger than comparable-mass galaxies in the local universe. Our observations suggest that quenching does not require the total removal or depletion of molecular gas, as many quenching models suggest. However, further observations are required both to determine if these apparently quiescent objects host highly obscured star formation and to investigate the intrinsic variation in the molecular gas properties of post-starburst galaxies.
|
28 |
Recalibration of the MBH–σ⋆ Relation for AGNBatiste, Merida, Bentz, Misty C., Raimundo, Sandra I., Vestergaard, Marianne, Onken, Christopher A. 24 March 2017 (has links)
We present a recalibration of the M-BH-sigma(star) relation, based on a sample of 16 reverberation-mapped galaxies with newly determined bulge stellar velocity dispersions (sigma(star)) from integral-field spectroscopy (IFS), and a sample of 32 quiescent galaxies with publicly available IFS. For both samples, sigma(star) is determined via two different methods that are popular in the literature, and we provide fits for each sample based on both sets of sigma(star). We find the fit to the active galactic nucleus sample is shallower than the fit to the quiescent galaxy sample, and that the slopes for each sample are in agreement with previous investigations. However, the intercepts to the quiescent galaxy relations are notably higher than those found in previous studies, due to the systematically lower sigma(star) measurements that we obtain from IFS. We find that this may be driven, in part, by poorly constrained measurements of bulge effective radius (r(e)) for the quiescent galaxy sample, which may bias the sigma(star) measurements low. We use these quiescent galaxy parameterizations, as well as one from the literature, to recalculate the virial scaling factor f. We assess the potential biases in each measurement, and suggest f = 4.82 +/- 1.67 as the best currently available estimate. However, we caution that the details of how sigma(star) is measured can significantly affect f, and there is still much room for improvement.
|
29 |
LOW GAS FRACTIONS CONNECT COMPACT STAR-FORMING GALAXIES TO THEIR z ∼ 2 QUIESCENT DESCENDANTSSpilker, Justin S., Bezanson, Rachel, Marrone, Daniel P., Weiner, Benjamin J., Whitaker, Katherine E., Williams, Christina C. 14 November 2016 (has links)
Early quiescent galaxies at z similar to 2 are known to be remarkably compact compared to their nearby counterparts. Possible progenitors of these systems include galaxies that are structurally similar, but are still rapidly forming stars. Here, we present Karl G. Jansky Very Large Array (VLA) observations of the CO(1-0) line toward three such compact, star-forming galaxies (SFGs) at z similar to 2.3, significantly detecting one. The VLA observations indicate baryonic gas fractions. greater than or similar to 5 times lower and gas depletion timescales. greater than or similar to 10 times shorter than normal, extended massive SFGs at these redshifts. At their current star formation rates, all three objects will deplete their gas reservoirs within 100 Myr. These objects are among the most gas-poor objects observed at z > 2, and are outliers from standard gas scaling relations, a result that remains true regardless of assumptions about the CO-H-2 conversion factor. Our observations are consistent with the idea that compact, SFGs are in a rapid state of transition to quiescence in tandem with the buildup of the z similar to 2 quenched population. In the detected compact galaxy, we see no evidence of rotation or that the CO-emitting gas is spatially extended relative to the stellar light. This casts doubt on recent suggestions that the gas in these compact galaxies is rotating and significantly extended compared to the stars. Instead, we suggest that, at least for this object, the gas is centrally concentrated, and only traces a small fraction of the total galaxy dynamical mass.
|
30 |
HIERARCHICAL FORMATION IN ACTION: CHARACTERIZING ACCELERATED GALAXY EVOLUTION IN COMPACT GROUPS USING WHOLE-SKY WISE DATAZucker, Catherine, Walker, Lisa May, Johnson, Kelsey, Gallagher, Sarah, Alatalo, Katherine, Tzanavaris, Panayiotis 20 April 2016 (has links)
Compact groups provide an environment to study the growth of galaxies amid multiple prolonged interactions. With their dense galaxy concentrations and relatively low velocity dispersions, compact groups mimic the conditions of hierarchical galaxy assembly. Compact group galaxies are known to show a bimodality in Spitzer IRAC infrared color space: galaxies are preferentially either quiescent with low specific star formation rates (SSFRs) or prolifically forming stars-galaxies with moderate levels of specific star formation are rare. Previous Spitzer IRAC studies identifying this "canyon" have been limited by small number statistics. We utilize whole-sky Wide-field Infrared Survey Explorer (WISE) data to study 163 compact groups, thereby tripling our previous sample and including more galaxies with intermediate mid-IR colors indicative of moderate SSFRs. We define a distinct WISE. mid-IR color space (log [f(12)/f(4.6)]) versus (log [f(22)/f(3.4)]) that we use to identify canyon galaxies from the larger sample. We confirm that compact group galaxies show a bimodal distribution in the mid-infrared and identify 37 canyon galaxies with reliable photometry and intermediate mid-IR colors. Morphologically, we find that the canyon harbors a large population of both Sa-Sbc and E/S0 type galaxies, and that they fall on the optical red sequence rather than the green valley. Finally, we provide a catalog of WISE. photometry for 567 of 652 galaxies selected from the sample of 163 compact groups.
|
Page generated in 0.0309 seconds