Collaborations with East Asian VLBI stations
... 4 others from VLBA • Pitch angle of Perseus arm 16 +/- 3 deg four arm spiral ? ...
... 4 others from VLBA • Pitch angle of Perseus arm 16 +/- 3 deg four arm spiral ? ...
The local spiral structure of the Milky Way
... main arc of the Local Arm. Instead, these sources, as well as G059.78+00.06 and ON 1, branch off and curve inward in the Milky Way. As the dotted line in Fig. 2 suggests, these sources trace what appears to be a high-inclination spur bridging the Local Arm to the Sagittarius Arm near l ≈ 50°. Additi ...
... main arc of the Local Arm. Instead, these sources, as well as G059.78+00.06 and ON 1, branch off and curve inward in the Milky Way. As the dotted line in Fig. 2 suggests, these sources trace what appears to be a high-inclination spur bridging the Local Arm to the Sagittarius Arm near l ≈ 50°. Additi ...
The 2008 RBSE Journal - National Optical Astronomy Observatory
... A Double Radio Source Associated with a Galactic Nucleus (DRAGN) is a radio source that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into exc ...
... A Double Radio Source Associated with a Galactic Nucleus (DRAGN) is a radio source that is produced by jets produced by active galactic nucleus that is not in the Milky Way. This happens when an accretion disk forms around a black hole and spins, converts gravitational and rotational energy into exc ...
The properties and evolution of low surface brightness galaxies de
... 2) is the dark matter distribution related to that of the light. The latter question can already be answered in the affirmative from the Tully-Fisher (TF) relation (Zwaan et al. 1995). Here, we confirm this with rotation curve decompositions of two galaxies selected for their nearly identical locati ...
... 2) is the dark matter distribution related to that of the light. The latter question can already be answered in the affirmative from the Tully-Fisher (TF) relation (Zwaan et al. 1995). Here, we confirm this with rotation curve decompositions of two galaxies selected for their nearly identical locati ...
The old globular cluster system of the dIrr galaxy NGC 1427A in the
... taken with the Hubble Space Telescope to reject contaminating background sources and blended objects from the GC candidates’ list. The Hα observations were used to check for contamination due to compact, highly reddened young star clusters whose colors and sizes could mimic those of old GCs. After a ...
... taken with the Hubble Space Telescope to reject contaminating background sources and blended objects from the GC candidates’ list. The Hα observations were used to check for contamination due to compact, highly reddened young star clusters whose colors and sizes could mimic those of old GCs. After a ...
Collisions and Encounters of Stellar Systems
... masses, and the violently changing gravitational field leads to a merger remnant that looks quite different from either of its progenitors. In contrast, minor mergers, in which one of the merging galaxies is much smaller than the other, leave the larger galaxy relatively unchanged. Not every close e ...
... masses, and the violently changing gravitational field leads to a merger remnant that looks quite different from either of its progenitors. In contrast, minor mergers, in which one of the merging galaxies is much smaller than the other, leave the larger galaxy relatively unchanged. Not every close e ...
13.1 Galaxy Evolution: Introduction
... interstellar medium. It also turns out that this is the estimated timescale of active galactic nucleus episodes, and it's not obvious whether this is coincidence or not. The internal timescales within galaxies are commensurate with their free-fall timescales, which would be ...
... interstellar medium. It also turns out that this is the estimated timescale of active galactic nucleus episodes, and it's not obvious whether this is coincidence or not. The internal timescales within galaxies are commensurate with their free-fall timescales, which would be ...
Clusters as laboratories for the study of galaxy evolution
... merging, it took place at higher redshifts (z >> 1 ) than is predicted by current semianalytical models.” p.s. van Dokkum and Stanford, 2003 ApJ, 585, 78, have measured velocity “…bright endfor of the was already in dispersions 3 ofLF the bright galaxies in this cluster, which confirm the large mass ...
... merging, it took place at higher redshifts (z >> 1 ) than is predicted by current semianalytical models.” p.s. van Dokkum and Stanford, 2003 ApJ, 585, 78, have measured velocity “…bright endfor of the was already in dispersions 3 ofLF the bright galaxies in this cluster, which confirm the large mass ...
IXO as an observatory in the large telescopes era
... indicating a geometrically thick torus around the SMBH (Ueda et al. 2007). This implies that many similar objects, if observed in edge-on geometry, could be missed in the current hard X-ray surveys due to the suppression of transmitted emission as they become heavily Compton thick (NH > a few 1024 c ...
... indicating a geometrically thick torus around the SMBH (Ueda et al. 2007). This implies that many similar objects, if observed in edge-on geometry, could be missed in the current hard X-ray surveys due to the suppression of transmitted emission as they become heavily Compton thick (NH > a few 1024 c ...
X. Nuclear star clusters in low-mass early-type galaxies
... At faint magnitudes, the dominant noise is a combination of the readnoise and the sky background noise with a small contribution of Poisson noise from the host galaxy (see also Section 4.3 and Fig. 6). For a host galaxy absolute magnitude MF814W = −13 mag, the difference between the host galaxy magn ...
... At faint magnitudes, the dominant noise is a combination of the readnoise and the sky background noise with a small contribution of Poisson noise from the host galaxy (see also Section 4.3 and Fig. 6). For a host galaxy absolute magnitude MF814W = −13 mag, the difference between the host galaxy magn ...
Galaxy formation in the Planck cosmology - II. Star
... Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH is often loosely used in papers without being defined. Observationally, the only direct measure of SFHs corresponds to that described in this paper, i.e. the distribution of formation times of all the ...
... Voort (2015). The difference between the two reflects the merger history of galaxies. The term SFH is often loosely used in papers without being defined. Observationally, the only direct measure of SFHs corresponds to that described in this paper, i.e. the distribution of formation times of all the ...
The Age Distribution of Potential Intelligent Life in the Milky Way
... From this equation we can see that the gas mass lost as it is turned into stars (per parsec squared per year) is proportional to the total mass of gas (per parsec squared) to the power n. Observations of distant galaxies have found this relationship to hold consistently, just with varying values of ...
... From this equation we can see that the gas mass lost as it is turned into stars (per parsec squared per year) is proportional to the total mass of gas (per parsec squared) to the power n. Observations of distant galaxies have found this relationship to hold consistently, just with varying values of ...
Full-text PDF
... 2003). In this paper we argue that radio sources may provide the required feedback while at the same time providing a solution to two other long-standing puzzles. An important unanswered question is why the gas at the centre of most galaxy clusters is apparently not condensing and turning into stars ...
... 2003). In this paper we argue that radio sources may provide the required feedback while at the same time providing a solution to two other long-standing puzzles. An important unanswered question is why the gas at the centre of most galaxy clusters is apparently not condensing and turning into stars ...
Messier 87
Messier 87 (also known as Virgo A or NGC 4486, and generally abbreviated to M87) is a supergiant elliptical galaxy in the constellation Virgo. One of the most massive galaxies in the local universe, it is notable for its large population of globular clusters—M87 contains about 12,000 compared to the 150-200 orbiting the Milky Way—and its jet of energetic plasma that originates at the core and extends outward at least 1,500 parsecs (4,900 light-years), travelling at relativistic speed. It is one of the brightest radio sources in the sky, and is a popular target for both amateur astronomy observations and professional astronomy study.French astronomer Charles Messier discovered M87 in 1781, cataloguing it as a nebulous feature while searching for objects that would confuse comet hunters. The second brightest galaxy within the northern Virgo Cluster, M87 is located about 16.4 million parsecs (53.5 million light-years) from Earth. Unlike a disk-shaped spiral galaxy, M87 has no distinctive dust lanes. Instead, it has an almost featureless, ellipsoidal shape typical of most giant elliptical galaxies, diminishing in luminosity with distance from the centre. Forming around one sixth of M87's mass, the stars in this galaxy have a nearly spherically symmetric distribution, their density decreasing with increasing distance from the core. At the core is a supermassive black hole, which forms the primary component of an active galactic nucleus. This object is a strong source of multiwavelength radiation, particularly radio waves. M87's galactic envelope extends out to a radius of about 150 kiloparsecs (490,000 light-years), where it has been truncated—possibly by an encounter with another galaxy. Between the stars is a diffuse interstellar medium of gas that has been chemically enriched by elements emitted from evolved stars.