the density profiles of massive, relaxed galaxy clusters. i. the total
... spectroscopy yielding seven new spectroscopic redshifts of multiply imaged sources and extended stellar velocity dispersion profiles of the BCGs. Lensing-derived mass profiles typically agree with independent X-ray estimates within 15%, suggesting that departures from hydrostatic equilibrium are sm ...
... spectroscopy yielding seven new spectroscopic redshifts of multiply imaged sources and extended stellar velocity dispersion profiles of the BCGs. Lensing-derived mass profiles typically agree with independent X-ray estimates within 15%, suggesting that departures from hydrostatic equilibrium are sm ...
A re-examination of galactic conformity and a comparison with semi
... The observed correlation between star formation in central galaxies and in their neighbours (a phenomenon dubbed ‘galactic conformity’) is in need of a convincing physical explanation. To gain further insight, we use a volume-limited sample of galaxies with redshifts less than 0.03 drawn from the Sl ...
... The observed correlation between star formation in central galaxies and in their neighbours (a phenomenon dubbed ‘galactic conformity’) is in need of a convincing physical explanation. To gain further insight, we use a volume-limited sample of galaxies with redshifts less than 0.03 drawn from the Sl ...
Extragalactic Astronomical Masers I
... occurring between the two different energy levels, which are the ground and upper states. The mechanism leading to the population inversion is the pump. Maser pumping is thus caused by the transitions of molecules between the two different energy levels. The mechanism that causes maser pumping is th ...
... occurring between the two different energy levels, which are the ground and upper states. The mechanism leading to the population inversion is the pump. Maser pumping is thus caused by the transitions of molecules between the two different energy levels. The mechanism that causes maser pumping is th ...
The Density Profiles of Massive, Relaxed Galaxy Clusters - HAL-Insu
... the stars trace the total gravitational potential (MiraldaEscude 1995; Natarajan & Kneib 1996). Spectroscopy using 8 − 10 m telescopes can reach from the stellardominated regime to the regime where DM is dynamically significant, even at the cosmological distances of lensing clusters (z & 0.2). Sand ...
... the stars trace the total gravitational potential (MiraldaEscude 1995; Natarajan & Kneib 1996). Spectroscopy using 8 − 10 m telescopes can reach from the stellardominated regime to the regime where DM is dynamically significant, even at the cosmological distances of lensing clusters (z & 0.2). Sand ...
MASSIVE GALAXIES IN COSMOLOGICAL SIMULATIONS: ULTRAVIOLET-SELECTED
... We study the properties of galaxies at redshift z ¼ 2 in a cold dark matter (CDM) universe, using two different types of hydrodynamic simulation methods—Eulerian total variation diminishing (TVD) and smoothed particle hydrodynamics (SPH)—and a spectrophotometric analysis in the Un , G, R filter s ...
... We study the properties of galaxies at redshift z ¼ 2 in a cold dark matter (CDM) universe, using two different types of hydrodynamic simulation methods—Eulerian total variation diminishing (TVD) and smoothed particle hydrodynamics (SPH)—and a spectrophotometric analysis in the Un , G, R filter s ...
STRUCTURAL CHARACTERISTICS AND STELLAR
... A few galaxies such as UGC 12695 have very bright H II regions. These may skew the luminosity weighted colors towards those of the H II regions. These can have peculiar colors because of the complex, rapidly evolving population of massive stars (Campbell & Terlevich 1984, McGaugh 1991), and because ...
... A few galaxies such as UGC 12695 have very bright H II regions. These may skew the luminosity weighted colors towards those of the H II regions. These can have peculiar colors because of the complex, rapidly evolving population of massive stars (Campbell & Terlevich 1984, McGaugh 1991), and because ...
Galaxy Evolution Over the Past Eleven Billion Years: Mergers and
... Galaxy evolution studies have been revolutionized by the advent of near-infrared observations over the last decade. An intriguingly population of distant red galaxies, only visible at near-infrared wavelengths, was discovered. They were previously overlooked, since they are invisible even in the dee ...
... Galaxy evolution studies have been revolutionized by the advent of near-infrared observations over the last decade. An intriguingly population of distant red galaxies, only visible at near-infrared wavelengths, was discovered. They were previously overlooked, since they are invisible even in the dee ...
The Hunt for Recoiled Black Holes in the Milky Way`s
... the merger history of the Milky Way, it is estimated there are ∼300 recoiled black holes in the halo. We present a preliminary spectroscopic search, using the search criteria and list of candidates in O’Leary & Loeb (2012). Although we did not find candidate recoiled black holes, we further optimize ...
... the merger history of the Milky Way, it is estimated there are ∼300 recoiled black holes in the halo. We present a preliminary spectroscopic search, using the search criteria and list of candidates in O’Leary & Loeb (2012). Although we did not find candidate recoiled black holes, we further optimize ...
exploring the universe with the low frequency array a scientific case
... bright stars and nebulae), the radio Universe appears very different from the visible Universe. During the last half century opening the radio Universe to astronomy therefore resulted in many unexpected discoveries. Synchrotron sources that will be observed by LOFAR include lobes and jets emitted by ...
... bright stars and nebulae), the radio Universe appears very different from the visible Universe. During the last half century opening the radio Universe to astronomy therefore resulted in many unexpected discoveries. Synchrotron sources that will be observed by LOFAR include lobes and jets emitted by ...
Galaxy Zoo: Are bars responsible for the feeding
... We present a new study investigating whether active galactic nuclei (AGN) beyond the local universe are preferentially fed via large-scale bars. Our investigation combines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS (All-wavelength Extended Groth strip International Survey), COSMOS ( ...
... We present a new study investigating whether active galactic nuclei (AGN) beyond the local universe are preferentially fed via large-scale bars. Our investigation combines data from Chandra and Galaxy Zoo: Hubble (GZH) in the AEGIS (All-wavelength Extended Groth strip International Survey), COSMOS ( ...
Observational evidence for AGN feedback in early
... 200 km s−1 ) and roughly evenly distributed between star formation and AGN at intermediate and low (σ < 100 km s−1 ) masses. The objects with emission (∼20 per cent) are offset from the red sequence and form a well-defined pattern in the colour–mass diagram. Star-forming early-types inhabit the blue ...
... 200 km s−1 ) and roughly evenly distributed between star formation and AGN at intermediate and low (σ < 100 km s−1 ) masses. The objects with emission (∼20 per cent) are offset from the red sequence and form a well-defined pattern in the colour–mass diagram. Star-forming early-types inhabit the blue ...
On the origin of lopsidedness in galaxies as determined
... inclination is clearly inappropriate. Instead, those studies must determine inclinations using a shape-independent approach, for example using the ratio of the H i line width, which is inclination-dependent, to the expected width calculated from the Tully–Fisher relation and the galaxy’s magnitude. ...
... inclination is clearly inappropriate. Instead, those studies must determine inclinations using a shape-independent approach, for example using the ratio of the H i line width, which is inclination-dependent, to the expected width calculated from the Tully–Fisher relation and the galaxy’s magnitude. ...
SPT 0538−50: PHYSICAL CONDITIONS IN THE ISM OF A STRONGLY... GALAXY AT Z=2.8
... SPT 0538−50 was observed with the Hubble Space Telescope Wide Field Camera 3 on 2011-10-10, as part of program 12659 (PI: Vieira). We use the F110W and F160W filters, the reddest high-throughput filters available. One complete orbit was dedicated to this source, split evenly between the two filters. ...
... SPT 0538−50 was observed with the Hubble Space Telescope Wide Field Camera 3 on 2011-10-10, as part of program 12659 (PI: Vieira). We use the F110W and F160W filters, the reddest high-throughput filters available. One complete orbit was dedicated to this source, split evenly between the two filters. ...
arXiv:astro-ph/0702414v1 15 Feb 2007
... to treat the radiation transfer of resonance lines, both numerically (e.g., Auer 1968; Adams 1972; Ahn et al. 2001; Richling 2003; Hansen & Oh 2006; Verhamme et al. 2006) and analytically (e.g., Osterbrock 1962; Neufeld 1990). Neutral hydrogen absorbs and re-emits Lyα photons in random directions. A ...
... to treat the radiation transfer of resonance lines, both numerically (e.g., Auer 1968; Adams 1972; Ahn et al. 2001; Richling 2003; Hansen & Oh 2006; Verhamme et al. 2006) and analytically (e.g., Osterbrock 1962; Neufeld 1990). Neutral hydrogen absorbs and re-emits Lyα photons in random directions. A ...
Vibrating Rays Theory arXiv:1407.5001v8
... of the Doppler data is that the signal is actively reflected, i.e. that the downlink signal is provided by an onboard spacecraft transmitter. While in SRT there is no difference between passive and active reflection, VRT produces different results. We will show that considering that difference it is ...
... of the Doppler data is that the signal is actively reflected, i.e. that the downlink signal is provided by an onboard spacecraft transmitter. While in SRT there is no difference between passive and active reflection, VRT produces different results. We will show that considering that difference it is ...
Redshift
In physics, redshift happens when light or other electromagnetic radiation from an object is increased in wavelength, or shifted to the red end of the spectrum. In general, whether or not the radiation is within the visible spectrum, ""redder"" means an increase in wavelength – equivalent to a lower frequency and a lower photon energy, in accordance with, respectively, the wave and quantum theories of light.Some redshifts are an example of the Doppler effect, familiar in the change of apparent pitches of sirens and frequency of the sound waves emitted by speeding vehicles. A redshift occurs whenever a light source moves away from an observer. Another kind of redshift is cosmological redshift, which is due to the expansion of the universe, and sufficiently distant light sources (generally more than a few million light years away) show redshift corresponding to the rate of increase in their distance from Earth. Finally, gravitational redshift is a relativistic effect observed in electromagnetic radiation moving out of gravitational fields. Conversely, a decrease in wavelength is called blueshift and is generally seen when a light-emitting object moves toward an observer or when electromagnetic radiation moves into a gravitational field. However, redshift is a more common term and sometimes blueshift is referred to as negative redshift.Knowledge of redshifts and blueshifts has been applied to develop several terrestrial technologies such as Doppler radar and radar guns. Redshifts are also seen in the spectroscopic observations of astronomical objects. Its value is represented by the letter z.A special relativistic redshift formula (and its classical approximation) can be used to calculate the redshift of a nearby object when spacetime is flat. However, in many contexts, such as black holes and Big Bang cosmology, redshifts must be calculated using general relativity. Special relativistic, gravitational, and cosmological redshifts can be understood under the umbrella of frame transformation laws. There exist other physical processes that can lead to a shift in the frequency of electromagnetic radiation, including scattering and optical effects; however, the resulting changes are distinguishable from true redshift and are not generally referred to as such (see section on physical optics and radiative transfer).