The XMM-Newton Bright Serendipitous Survey
... Ceca et al. 2004) and the brightness of the sources: X-ray sources with FX >10−13 erg cm−2 s−1 are expected to have an optical counterpart brighter than 22 mag for X-ray-to-optical flux ratios below 20 (i.e. for the majority of type 1 AGN, galaxies and stars). Only the rare (but interesting) sources ...
... Ceca et al. 2004) and the brightness of the sources: X-ray sources with FX >10−13 erg cm−2 s−1 are expected to have an optical counterpart brighter than 22 mag for X-ray-to-optical flux ratios below 20 (i.e. for the majority of type 1 AGN, galaxies and stars). Only the rare (but interesting) sources ...
Galaxy Assembly through Mergers
... of star formation to severe morphological changes. On the other hand, for mergers between elliptical, gas-poor galaxies, the apparent absence of strong perturbations poses another challenge, even though, given their massive nature, they may be responsible for the high mass end of the mass function. ...
... of star formation to severe morphological changes. On the other hand, for mergers between elliptical, gas-poor galaxies, the apparent absence of strong perturbations poses another challenge, even though, given their massive nature, they may be responsible for the high mass end of the mass function. ...
Niraj D. Welikala Thesis - D-Scholarship@Pitt
... sampling a wide range of properties such as age, star formation rate (SFR), dust obscuration and metallicity. By summing the SFRs in the pixels, I show that, as found in other studies, the distribution of total galaxy SFR shifts to lower values as the local density of surrounding galaxies increases. ...
... sampling a wide range of properties such as age, star formation rate (SFR), dust obscuration and metallicity. By summing the SFRs in the pixels, I show that, as found in other studies, the distribution of total galaxy SFR shifts to lower values as the local density of surrounding galaxies increases. ...
Galaxy And Mass Assembly (GAMA): Gas Fueling of Spiral Galaxies
... et al. 2011). For cosmological DMH detailed thermodynamic considerations of this process find a transition mass between these two modes, i.e., where the free-fall timescale equals the cooling timescale at the virial radius of ∼1011–1012 Me (Kereš et al. 2005; Dekel & Birnboim 2006).20 As such, the ac ...
... et al. 2011). For cosmological DMH detailed thermodynamic considerations of this process find a transition mass between these two modes, i.e., where the free-fall timescale equals the cooling timescale at the virial radius of ∼1011–1012 Me (Kereš et al. 2005; Dekel & Birnboim 2006).20 As such, the ac ...
... disks out of disk material. These are called pseudobulges. Our discussion updates a review by Kormendy (1993). The relative importance of the different physical processes of galaxy evolution (Figure 1) changes as the Universe expands. Rapid processes that happen in discrete events are giving way to ...
environmental effects on galaxy evolution in nearby clusters
... This work represents the end point of my student career. After approximately twenty one years from my first entrance in a class room (it was September 1984 in Phoenix, AZ), I’m finally going to attend my last ”school” examination. Therefore I want to seize this opportunity in order to briefly rememb ...
... This work represents the end point of my student career. After approximately twenty one years from my first entrance in a class room (it was September 1984 in Phoenix, AZ), I’m finally going to attend my last ”school” examination. Therefore I want to seize this opportunity in order to briefly rememb ...
Galaxy Morphology - The University of Alabama
... but we usually cannot know both well from inspection of images alone. Galaxy morphology began to get interesting when the “Leviathan of Parsonstown”, the 72-inch meridian-based telescope built in the 1840s by William Parsons, Third Earl of Rosse, on the grounds of Birr Castle in Ireland, revealed sp ...
... but we usually cannot know both well from inspection of images alone. Galaxy morphology began to get interesting when the “Leviathan of Parsonstown”, the 72-inch meridian-based telescope built in the 1840s by William Parsons, Third Earl of Rosse, on the grounds of Birr Castle in Ireland, revealed sp ...
Hubble 2006: Science Year in Review
... Hubble’s most powerful camera, the Advanced Camera for Surveys (ACS), providing a tenfold improvement over WFPC2. The final servicing mission in 2008 will install two new instruments, the Cosmic Origins Spectrograph (COS) and Wide Field Camera 3 (WFC3). COS is the most sensitive ultraviolet spectrog ...
... Hubble’s most powerful camera, the Advanced Camera for Surveys (ACS), providing a tenfold improvement over WFPC2. The final servicing mission in 2008 will install two new instruments, the Cosmic Origins Spectrograph (COS) and Wide Field Camera 3 (WFC3). COS is the most sensitive ultraviolet spectrog ...
Galaxy pairs in the Sloan Digital Sky Survey III. Evidence of induced
... sample of non-interacting galaxies. However, if one simply selects galaxies at random from the remaining (non-paired) galaxies in the catalogue, the resulting distribution of stellar masses and redshifts will be significantly different from the pairs sample (Ellison et al. 2008; Perez, Tissera & Bla ...
... sample of non-interacting galaxies. However, if one simply selects galaxies at random from the remaining (non-paired) galaxies in the catalogue, the resulting distribution of stellar masses and redshifts will be significantly different from the pairs sample (Ellison et al. 2008; Perez, Tissera & Bla ...
Isolated elliptical galaxies in the local Universe
... fraction of ellipticals with younger stellar populations is predicted than in clusters (Kauffmann 1996; Niemi et al. 2010). This may indicate different formation histories. Theoretical models suggest that ellipticals in clusters form through dissipative infall of gas and numerous mergers that took pla ...
... fraction of ellipticals with younger stellar populations is predicted than in clusters (Kauffmann 1996; Niemi et al. 2010). This may indicate different formation histories. Theoretical models suggest that ellipticals in clusters form through dissipative infall of gas and numerous mergers that took pla ...
The VIMOS Ultra-Deep Survey (VUDS): Fast Increase in the Fraction
... the Lyα escape fraction (i.e., the fraction of the Lyα photons that escape the galaxies) that depends strongly on the relative kinematics of the HII and HI regions, dust content, and geometry (Giavalisco et al. 1996; Kunth et al. 1998; Mas-Hesse et al. 2003; Deharveng et al. 2008; Hayes et al. 2014) ...
... the Lyα escape fraction (i.e., the fraction of the Lyα photons that escape the galaxies) that depends strongly on the relative kinematics of the HII and HI regions, dust content, and geometry (Giavalisco et al. 1996; Kunth et al. 1998; Mas-Hesse et al. 2003; Deharveng et al. 2008; Hayes et al. 2014) ...
THE UV-OPTICAL COLOR MAGNITUDE DIAGRAM. II. PHYSICAL
... We use the UV-optical color magnitude diagram in combination with spectroscopic and photometric measurements derived from the SDSS spectroscopic sample to measure the distribution of galaxies in the local universe (z < 0:25) and their physical properties as a function of specific star formation rate ...
... We use the UV-optical color magnitude diagram in combination with spectroscopic and photometric measurements derived from the SDSS spectroscopic sample to measure the distribution of galaxies in the local universe (z < 0:25) and their physical properties as a function of specific star formation rate ...
Revising the census of low luminosity AGN
... A LOW EW (~1 Å) IS CHARACTERISTIC OF STELLAR PROCESSES AGN 10 - Roma 10/09/2012 ...
... A LOW EW (~1 Å) IS CHARACTERISTIC OF STELLAR PROCESSES AGN 10 - Roma 10/09/2012 ...
Observational Studies of Interacting Galaxies and the Development
... we worked on together. I have learned a lot from you, including how to conduct observations, reduce data and write papers, etc. Suresh, I owe you a big thank for helping me in instrument developments. I have learned basic optics, experimental techniques and trouble shooting from you. I really enjoye ...
... we worked on together. I have learned a lot from you, including how to conduct observations, reduce data and write papers, etc. Suresh, I owe you a big thank for helping me in instrument developments. I have learned basic optics, experimental techniques and trouble shooting from you. I really enjoye ...
The most metal-poor galaxies
... the process of formation, because of their extreme metal under-abundance, more than 10 times less than solar, and even more extreme than that of HII regions found in the outskirts of spiral galaxies. At the time of this discovery the general wisdom that most galaxies (in particular the ellipticals) ...
... the process of formation, because of their extreme metal under-abundance, more than 10 times less than solar, and even more extreme than that of HII regions found in the outskirts of spiral galaxies. At the time of this discovery the general wisdom that most galaxies (in particular the ellipticals) ...
The correlation between galaxy morphology and star
... et al. 2010; Cassata et al. 2010). The number density of these galaxies rapidly increases, by a factor of five, from z ∼ 2 to z ∼ 1, and they are up to 5 times more compact in size than local ones with similar mass (Cassata et al. 2011, 2013). Recent works have suggested, however, that a large fract ...
... et al. 2010; Cassata et al. 2010). The number density of these galaxies rapidly increases, by a factor of five, from z ∼ 2 to z ∼ 1, and they are up to 5 times more compact in size than local ones with similar mass (Cassata et al. 2011, 2013). Recent works have suggested, however, that a large fract ...
Jul y 10-12,
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
... Almost all Galactic black hole (BH) binaries with low mass donors are transient X-ray sources; we expect most of the X-ray transients (XRTs) observed in external galaxies to be BH binaries also. Obtaining period estimates for extra-galactic XRTs is challenging, but the resulting period distribution ...
Morphological evolution of galaxies over the last 8 billion years
... the evolution of the diffuse baryonic component. According to these models not only massive galaxies form by merging of smaller ones, but also bulge dominated galaxies form from disks, either through mergers or by dynamical instabilities. Therefore, at the same time, both the number density of the m ...
... the evolution of the diffuse baryonic component. According to these models not only massive galaxies form by merging of smaller ones, but also bulge dominated galaxies form from disks, either through mergers or by dynamical instabilities. Therefore, at the same time, both the number density of the m ...
A simple model to interpret the ultraviolet, optical and infrared
... Astronomical Satellite (IRAS; Beichman et al. 1988), the Infrared Space Observatory (ISO; Kessler et al. 1996) and the Spitzer Space Telescope (Werner et al. 2004), and in the submillimetre by the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (Holland et al. ...
... Astronomical Satellite (IRAS; Beichman et al. 1988), the Infrared Space Observatory (ISO; Kessler et al. 1996) and the Spitzer Space Telescope (Werner et al. 2004), and in the submillimetre by the Submillimetre Common User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (Holland et al. ...
Preliminary Talk Abstract Book - MoCA
... outflow rates even at low redshift, which change its morphology. Interestingly, it maintains a relatively low star formation rate, even though only stellar feedback and no black hole feedback is implemented. The outflows generated by supernovae can shock, reach high temperatures, and emit X-ray radi ...
... outflow rates even at low redshift, which change its morphology. Interestingly, it maintains a relatively low star formation rate, even though only stellar feedback and no black hole feedback is implemented. The outflows generated by supernovae can shock, reach high temperatures, and emit X-ray radi ...
ROSAT Ian R. Stevens* and David K. Strickland*
... spectra with typically kT , 0:4¹1:0 keV. There are some oddities: NGC 5408 is very overluminous in X-rays, even compared with other WR galaxies; I Zw 18 has a harder Xray spectrum; NGC 1365, although thought to contain an active nucleus, has X-ray properties that are broadly similar to other WR gala ...
... spectra with typically kT , 0:4¹1:0 keV. There are some oddities: NGC 5408 is very overluminous in X-rays, even compared with other WR galaxies; I Zw 18 has a harder Xray spectrum; NGC 1365, although thought to contain an active nucleus, has X-ray properties that are broadly similar to other WR gala ...
Gamma-Ray Bursts and Puzzles of Core
... corrected for galactic extinction. Synthetic spectra are shown by smooth lines. Locations of spectral lines of some ions and blends of their lines are shown in those parts of the spectrum where contribution of this ion into the spectrum is essential for given model parameters. The black line is the ...
... corrected for galactic extinction. Synthetic spectra are shown by smooth lines. Locations of spectral lines of some ions and blends of their lines are shown in those parts of the spectrum where contribution of this ion into the spectrum is essential for given model parameters. The black line is the ...
IRAM Annual Report 2011
... comparable blue and red components, with a strikingly broad blue component, suggesting strong ionized gas flows. The system, even when the amplification factor is taken into account, is hyper-luminous (>1013 L⊙, or 2-3 orders of magnitude more than the Milky Way), which is remarkable for an object f ...
... comparable blue and red components, with a strikingly broad blue component, suggesting strong ionized gas flows. The system, even when the amplification factor is taken into account, is hyper-luminous (>1013 L⊙, or 2-3 orders of magnitude more than the Milky Way), which is remarkable for an object f ...
- Isaac Newton Group of Telescopes
... was confirmed to coincide with that of the stars of the cluster and, later, a precise photometric characterization was achieved. Several high resolution spectra between 600 and 900 nm were obtained with the WHT. These spectra confirmed the discovery of one of the coldest quasi-stellar objects known ...
... was confirmed to coincide with that of the stars of the cluster and, later, a precise photometric characterization was achieved. Several high resolution spectra between 600 and 900 nm were obtained with the WHT. These spectra confirmed the discovery of one of the coldest quasi-stellar objects known ...
Identifying the progenitor set of present-day early
... evolve without interactions thereafter, while in the field the corresponding value is ∼30 percent. Averaging across all environments at z ∼ 1, less than 50 percent of the stellar mass which ends up in early-types today is actually in early-type progenitors at this redshift, in agreement with recent ...
... evolve without interactions thereafter, while in the field the corresponding value is ∼30 percent. Averaging across all environments at z ∼ 1, less than 50 percent of the stellar mass which ends up in early-types today is actually in early-type progenitors at this redshift, in agreement with recent ...
Quasar
Quasars (/ˈkweɪzɑr/) or quasi-stellar radio sources are the most energetic and distant members of a class of objects called active galactic nuclei (AGN). Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that appeared to be similar to stars, rather than extended sources similar to galaxies. Their spectra contain very broad emission lines, unlike any known from stars, hence the name ""quasi-stellar."" Their luminosity can be 100 times greater than that of the Milky Way. Most quasars were formed approximately 12 billion years ago caused by collisions of galaxies and their central black holes merging to form either a supermassive black hole or a Binary black hole system.Although the true nature of these objects was controversial until the early 1980s, there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding a central supermassive black hole. Its size is 10–10,000 times the Schwarzschild radius of the black hole. The energy emitted by a quasar derives from mass falling onto the accretion disc around the black hole.