talk
... – 5 kpc versus 900 pc for nine galaxies • 5 local galaxies have two nuclei separated by 4-32 kpc • These galaxies are at faint luminosity end of our sample ...
... – 5 kpc versus 900 pc for nine galaxies • 5 local galaxies have two nuclei separated by 4-32 kpc • These galaxies are at faint luminosity end of our sample ...
ALMA_BoJun605_Gruppioni
... The ability to detect spectral line emission from CO or CI in a normal galaxy like the Milky Way at a redshift of 3, in less than 24 hours of observation. ...
... The ability to detect spectral line emission from CO or CI in a normal galaxy like the Milky Way at a redshift of 3, in less than 24 hours of observation. ...
lecture2_3
... •Study their motions, measure their speeds •Fundamental to understand the evolution of the sources and how their interact with each other (e.g. merging, collisions) •Measure their redshift, determine their distance from us •Fundamental to chart the large-scale structure of the Universe and to study ...
... •Study their motions, measure their speeds •Fundamental to understand the evolution of the sources and how their interact with each other (e.g. merging, collisions) •Measure their redshift, determine their distance from us •Fundamental to chart the large-scale structure of the Universe and to study ...
VERA Project : overview and current status
... Near-future projects for 10 micro-arcsec astrometry ...
... Near-future projects for 10 micro-arcsec astrometry ...
High-mass star-forming cloud G0.38+0.04 in the Galactic center dust
... Sgr B2 (M): there is only one SiO maser spot in Sgr B2, located near Mehringer et al. (1994) H2 CO Source C (not to be confused with Cloud C, the topic of this paper). The Sgr B2 H2 CO maser C is peculiar even among the Sgr B2 masers in that the emission appears to be spatially and spectrally resolv ...
... Sgr B2 (M): there is only one SiO maser spot in Sgr B2, located near Mehringer et al. (1994) H2 CO Source C (not to be confused with Cloud C, the topic of this paper). The Sgr B2 H2 CO maser C is peculiar even among the Sgr B2 masers in that the emission appears to be spatially and spectrally resolv ...
Active Galactic Nuclei - University of Toronto
... When viewed in the radio spectrum, one can notice the following: • The nucleus – the centre of the galaxy • Jets - bright lines where strong radio emission streams out from the nucleus • Lobes – region around the jets • Plumes – similar to lobes, yet they have a much more elongated structure, replac ...
... When viewed in the radio spectrum, one can notice the following: • The nucleus – the centre of the galaxy • Jets - bright lines where strong radio emission streams out from the nucleus • Lobes – region around the jets • Plumes – similar to lobes, yet they have a much more elongated structure, replac ...
Presentazione di PowerPoint
... detection threshold (in the range 5-10 ) The detected maser spots have been fitted with two-dimensional elliptical Gaussians (intensities in the range: 0.3-17 Jy beam-1) A maser “feature” is considered real if it is detected in at least three contiguous channels (spectral FWHM > 0.3 km/s), with a ...
... detection threshold (in the range 5-10 ) The detected maser spots have been fitted with two-dimensional elliptical Gaussians (intensities in the range: 0.3-17 Jy beam-1) A maser “feature” is considered real if it is detected in at least three contiguous channels (spectral FWHM > 0.3 km/s), with a ...
Molecular Line Emission in Star
... A particular case of molecular lines are Masers (Microwave Amplification by the Stimulated Emission of Radiation): Under normal conditions of thermal equilibrium, the number of particles in lower energy levels is always greater than the number in higher energy levels, this leads to radiation being a ...
... A particular case of molecular lines are Masers (Microwave Amplification by the Stimulated Emission of Radiation): Under normal conditions of thermal equilibrium, the number of particles in lower energy levels is always greater than the number in higher energy levels, this leads to radiation being a ...
3P31.pdf
... • CB 101 had also been reported as a starless core (Lee & Myers 1999). Moreover, Clemens et al (1991) classified it as a cool and quiescent cloud. Our recent IRAM-30m observations do not show any high-velocity ourflow, and the maser is not even associated with significant amounts of molecular gas. T ...
... • CB 101 had also been reported as a starless core (Lee & Myers 1999). Moreover, Clemens et al (1991) classified it as a cool and quiescent cloud. Our recent IRAM-30m observations do not show any high-velocity ourflow, and the maser is not even associated with significant amounts of molecular gas. T ...
aaswinter07ppt
... • The detailed light curve is unlike that of a supernova, nova, or any other type of variable star (1,2,3). During the outburst, V838 Mon was found to have a maximum effective temperature of an A – F star at the optical maximum in February 2002. The effective temperature then cooled to a very low ~8 ...
... • The detailed light curve is unlike that of a supernova, nova, or any other type of variable star (1,2,3). During the outburst, V838 Mon was found to have a maximum effective temperature of an A – F star at the optical maximum in February 2002. The effective temperature then cooled to a very low ~8 ...
aaswinter06
... • The detailed light curve is unlike that of a supernova, nova, or any other type of variable star (1,2,3). During the outburst, V838 Mon was found to have a maximum effective temperature of an A – F star at the optical maximum in February 2002. The effective temperature then cooled to a very low ~8 ...
... • The detailed light curve is unlike that of a supernova, nova, or any other type of variable star (1,2,3). During the outburst, V838 Mon was found to have a maximum effective temperature of an A – F star at the optical maximum in February 2002. The effective temperature then cooled to a very low ~8 ...
Spectral Line VLBI - Australia Telescope National Facility
... • The maser components are extremely small (mas) and narrow (fractions of a km/s) Measure position and velocity of components with great accuracy ...
... • The maser components are extremely small (mas) and narrow (fractions of a km/s) Measure position and velocity of components with great accuracy ...
The phenomena of astrophysical masers are not new by any means
... stimulated absorption of radiation. The discovery of naturally occurring masers has created new opportunities for exploring the universe. They provide the ability to see into the center of some galaxies obscured by dust and gas. The discovery of water masers in galaxies billions of light years away ...
... stimulated absorption of radiation. The discovery of naturally occurring masers has created new opportunities for exploring the universe. They provide the ability to see into the center of some galaxies obscured by dust and gas. The discovery of water masers in galaxies billions of light years away ...
Megamaser
A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. Megamasers are distinguished from astrophysical masers by their large isotropic luminosity. Megamasers have typical luminosities of 103 solar luminosities (L☉), which is 100 million times brighter than masers in the Milky Way, hence the prefix mega. Likewise, the term kilomaser is used to describe masers outside the Milky Way that have luminosities of order L☉, or thousands of times stronger than the average maser in the Milky Way, gigamaser is used to describe masers billions of times stronger than the average maser in the Milky Way, and extragalactic maser encompasses all masers found outside the Milky Way. Most known extragalactic masers are megamasers, and the majority of megamasers are hydroxyl (OH) megamasers, meaning the spectral line being amplified is one due to a transition in the hydroxyl molecule. There are known megamasers for three other molecules: water (H2O), formaldehyde (H2CO), and methine (CH).Water megamasers were the first type of megamaser discovered. The first water megamaser was found in 1979 in NGC 4945, a galaxy in the nearby Centaurus A/M83 Group. The first hydroxyl megamaser was found in 1982 in Arp 220, which is the nearest ultraluminous infrared galaxy to the Milky Way. All subsequent OH megamasers that have been discovered are also in luminous infrared galaxies, and there are a small number of OH kilomasers hosted in galaxies with lower infrared luminosities. Most luminous infrared galaxies have recently merged or interacted with another galaxy, and are undergoing a burst of star formation. Many of the characteristics of the emission in hydroxyl megamasers are distinct from that of hydroxyl masers within the Milky Way, including the amplification of background radiation and the ratio of hydroxyl lines at different frequencies. The population inversion in hydroxyl molecules is produced by far infrared radiation that results from absorption and re-emission of light from forming stars by surrounding interstellar dust. Zeeman splitting of hydroxyl megamaser lines may be used to measure magnetic fields in the masing regions, and this application represents the first detection of Zeeman splitting in a galaxy other than the Milky Way.Water megamasers and kilomasers are found primarily associated with active galactic nuclei, while galactic and weaker extragalactic water masers are found in star forming regions. Despite different environments, the circumstances that produce extragalactic water masers do not seem to be very different from those that produce galactic water masers. Observations of water megamasers have been used to make accurate measurements of distances to galaxies in order to provide constraints on the Hubble constant.