Supernovae and Gamma-Ray Bursts (draft)
... their H-rich envelopes and, in the case of SNe Ic, their He-rich layers as well.5 There are also several different sub-types of Type I supernovae. Unlike SNe I, they are not always defined by their spectroscopic properties but by their lightcurves, i.e., their luminosity, measured in a particular wa ...
... their H-rich envelopes and, in the case of SNe Ic, their He-rich layers as well.5 There are also several different sub-types of Type I supernovae. Unlike SNe I, they are not always defined by their spectroscopic properties but by their lightcurves, i.e., their luminosity, measured in a particular wa ...
Star Formation and Young Clusters in Cygnus
... the large cloud Kh 141 = TGU 541 associated with or in the line of sight towards the Cyg OB7 association. The small compact cloud which harbors the active star forming region IC 5146 (see the chapter in this book by Herbig & Reipurth) is at lower Galactic latitudes. Figure 2 shows the cloud identifi ...
... the large cloud Kh 141 = TGU 541 associated with or in the line of sight towards the Cyg OB7 association. The small compact cloud which harbors the active star forming region IC 5146 (see the chapter in this book by Herbig & Reipurth) is at lower Galactic latitudes. Figure 2 shows the cloud identifi ...
Pre-main sequence stars, emission stars and recent star formation in
... studied here are Berkeley 86, NGC 6910, IC 4996, Berkeley 87 and Biurakan 2. We aim to combine the ages and the star formation duration in these clusters to understand how the star formation proceeded in the Cygnus region. A number of stars are known to show Hα emission in this region. The photometr ...
... studied here are Berkeley 86, NGC 6910, IC 4996, Berkeley 87 and Biurakan 2. We aim to combine the ages and the star formation duration in these clusters to understand how the star formation proceeded in the Cygnus region. A number of stars are known to show Hα emission in this region. The photometr ...
The chemical enrichment of the ICM from hydrodynamical simulations
... formation, associated to the cooling of the gas infalling in high density regions. In this sense, a fully self–consistent approach requires that the simulations include the processes of gas cooling, star formation and evolution, along with the corresponding feedback in energy and metals. A number of ...
... formation, associated to the cooling of the gas infalling in high density regions. In this sense, a fully self–consistent approach requires that the simulations include the processes of gas cooling, star formation and evolution, along with the corresponding feedback in energy and metals. A number of ...
Science with IMACS on Magellan
... gradients in the halos of nearby brighter galaxies such as those of the Sculptor group. They are particularly interested in using the tip of the red giant branch as a distance indicator to nearby galaxies with a wide range of metal abundances, as a check of possible dependences of Cepheid-based dist ...
... gradients in the halos of nearby brighter galaxies such as those of the Sculptor group. They are particularly interested in using the tip of the red giant branch as a distance indicator to nearby galaxies with a wide range of metal abundances, as a check of possible dependences of Cepheid-based dist ...
Stellar contents and star formation in the young open cluster Stock 8
... dynamical evolution, their mass function (MF) can be considered as the IMF. However, a recent study by Kroupa (2007) argues that even in the youngest clusters, it is difficult to trace the IMF, as clusters evolve rapidly and therefore eject a fraction of their members even at a very young age. There ...
... dynamical evolution, their mass function (MF) can be considered as the IMF. However, a recent study by Kroupa (2007) argues that even in the youngest clusters, it is difficult to trace the IMF, as clusters evolve rapidly and therefore eject a fraction of their members even at a very young age. There ...
rcw 49 at mid-infrared wavelengths: a glimpse from the
... the [3.6], [4.5], and [5.8] bands, and the right panels are composites of the [3.6], [5.8], and [8.0] bands. These color combinations were chosen to highlight particular properties of the images described below. The same general features are seen in both of the three-color images, but there are impo ...
... the [3.6], [4.5], and [5.8] bands, and the right panels are composites of the [3.6], [5.8], and [8.0] bands. These color combinations were chosen to highlight particular properties of the images described below. The same general features are seen in both of the three-color images, but there are impo ...
Bright 22 μm excess candidates from the wise all-sky
... it may be produced by protostars (Thompson 1982), surrounding disk dust (Gorlova et al. 2004, 2006; Rhee et al. 2007; Hovhannisyan et al. 2009; Koerner et al. 2010; Wu et al. 2012), or giant stars, or it could also be due to M dwarfs or brown dwarfs (Debes et al. 2011). However, excess IR could also ...
... it may be produced by protostars (Thompson 1982), surrounding disk dust (Gorlova et al. 2004, 2006; Rhee et al. 2007; Hovhannisyan et al. 2009; Koerner et al. 2010; Wu et al. 2012), or giant stars, or it could also be due to M dwarfs or brown dwarfs (Debes et al. 2011). However, excess IR could also ...
1 The Hubble Story (10:56)
... versatility has allowed it to make significant contributions to the field. For example, Hubble’s high resolution has been indispensable in the investigation of the gas and dust disks, dubbed proplyds, around the newly born stars in the Orion Nebula. The proplyds may very well be young planetary syst ...
... versatility has allowed it to make significant contributions to the field. For example, Hubble’s high resolution has been indispensable in the investigation of the gas and dust disks, dubbed proplyds, around the newly born stars in the Orion Nebula. The proplyds may very well be young planetary syst ...
HS 0702+6043: a star showing both short-period p
... we can easily exclude a potential F- or G-type main sequence companion. Because the star is relatively faint, 2MASS photometry is only accurate enough to require that any hypothetical companion must be later than K-type. At the supposed 1 h orbit, the Roche geometry marginally allows to fit an objec ...
... we can easily exclude a potential F- or G-type main sequence companion. Because the star is relatively faint, 2MASS photometry is only accurate enough to require that any hypothetical companion must be later than K-type. At the supposed 1 h orbit, the Roche geometry marginally allows to fit an objec ...
AN INTENSIVE HUBBLE SPACE TELESCOPE
... Additional observations indicate that SNe Ia properties are correlated with host-galaxy properties. The average SN Ia hosted by a passive galaxy has a faster rise and fall than the average SN Ia hosted by a star-forming galaxy (Sullivan et al. 2006). The rate of SN Ia production per unit mass increa ...
... Additional observations indicate that SNe Ia properties are correlated with host-galaxy properties. The average SN Ia hosted by a passive galaxy has a faster rise and fall than the average SN Ia hosted by a star-forming galaxy (Sullivan et al. 2006). The rate of SN Ia production per unit mass increa ...
A" Light," Centrally-Concentrated Milky Way Halo?
... Mvir = 8×1011 M⊙ MW-sized disk galaxy (Guedes et al. 2011), as well as the more massive, Mvir = 1.7 × 1012 M⊙ , dark-matter only Via Lactea II (VLII) simulation (Diemand et al. 2008). Eris is the first simulated galaxy in a ΛCDM cosmology in which the galaxy structural properties, mass budget in the ...
... Mvir = 8×1011 M⊙ MW-sized disk galaxy (Guedes et al. 2011), as well as the more massive, Mvir = 1.7 × 1012 M⊙ , dark-matter only Via Lactea II (VLII) simulation (Diemand et al. 2008). Eris is the first simulated galaxy in a ΛCDM cosmology in which the galaxy structural properties, mass budget in the ...
From ATLASGAL to SEDIGISM: Towards a Complete 3D View of the
... Spectroscopic follow-ups Continuum observations can be affected by line-of-sight projection effects, which make it difficult to determine whether a detected structure is a single, coherent object. Spectroscopic follow-up observations are crucial to measure (local standard of rest) radial velocities ...
... Spectroscopic follow-ups Continuum observations can be affected by line-of-sight projection effects, which make it difficult to determine whether a detected structure is a single, coherent object. Spectroscopic follow-up observations are crucial to measure (local standard of rest) radial velocities ...
N-body Simulations and Galaxy Formation
... merger simulations of disk galaxies. However, the resolution of these simulations was very low and the number of particles representing each galaxy did not exceed 500. The situation changed with the advent of Treecodes in the late 1980s (Appel, 1985; Jernigan, 1985; Barnes, 1986; Hernquist, 1987; Je ...
... merger simulations of disk galaxies. However, the resolution of these simulations was very low and the number of particles representing each galaxy did not exceed 500. The situation changed with the advent of Treecodes in the late 1980s (Appel, 1985; Jernigan, 1985; Barnes, 1986; Hernquist, 1987; Je ...
Chemical composition of halo and disk stars with
... groups were defined according to the criteria: i) Vrot < 50 km s−1 ; the halo stars. ii) Vrot > 150 km s−1 ; the disk stars. We aimed at observing about the same number of halo and disk stars, and furthermore to have as far as possible the same distribution in [Fe/H] for the two groups. Obviously, o ...
... groups were defined according to the criteria: i) Vrot < 50 km s−1 ; the halo stars. ii) Vrot > 150 km s−1 ; the disk stars. We aimed at observing about the same number of halo and disk stars, and furthermore to have as far as possible the same distribution in [Fe/H] for the two groups. Obviously, o ...
Cygnus X-1 poster (Massive Star Workshop)
... derived in Section 5, which is 22–32 km s . from the Sun, with a Galactic longitude l = 71.◦range 3, and a Galactic by m subject to secular changes due to the tidal torque exerted by In addition, there are two more restrictions on the properties of 2σ ...
... derived in Section 5, which is 22–32 km s . from the Sun, with a Galactic longitude l = 71.◦range 3, and a Galactic by m subject to secular changes due to the tidal torque exerted by In addition, there are two more restrictions on the properties of 2σ ...
FY1995 Q1 Oct-Dec NO.. - National Optical Astronomy Observatory
... 2. Detection of Lens Candidates for the Double Quasar Q2345+007 The object called Q2345+007 AB is actually a pair of quasars that appear to lie about 7" apart on the sky. The two components (A and B) have very similar spectra and redshifts (z = 2.15), raising the possibility that the pair is part of ...
... 2. Detection of Lens Candidates for the Double Quasar Q2345+007 The object called Q2345+007 AB is actually a pair of quasars that appear to lie about 7" apart on the sky. The two components (A and B) have very similar spectra and redshifts (z = 2.15), raising the possibility that the pair is part of ...
Photometric catalog of nearby globular clusters
... In the next subsections, we briefly present the single CMDs and clusters, and give some references to the best existing CMDs. This does not pretend to be a complete bibliographical catalog: a large number of CMDs are available in the literature for many of the clusters of this survey; we will concen ...
... In the next subsections, we briefly present the single CMDs and clusters, and give some references to the best existing CMDs. This does not pretend to be a complete bibliographical catalog: a large number of CMDs are available in the literature for many of the clusters of this survey; we will concen ...
OUTFLOW INFALL AND ROTATION IN HIGH
... • In Lstar ~ 104 LO (B stars) true disks found • In Lstar > 105 LO (O stars) no true disk (only toroids) found - but distance is large (few kpc) • Orion I (450 pc) does have disk, but luminosity is unclear (< 105 LO???) Difficult to detect massive disks in O (proto)stars. Why? ...
... • In Lstar ~ 104 LO (B stars) true disks found • In Lstar > 105 LO (O stars) no true disk (only toroids) found - but distance is large (few kpc) • Orion I (450 pc) does have disk, but luminosity is unclear (< 105 LO???) Difficult to detect massive disks in O (proto)stars. Why? ...
Gamma Ray Burst Afterglows and Host Galaxies
... Proof of Relativistic Speeds • Interstellar gas in our Galaxy causes small radio sources to “twinkle” (like stars seen in visible light through our atmosphere). • Larger sources do not twinkle (like planets). • Measuring the time when an afterglow stops “twinkling” at radio wavelengths reveals its ...
... Proof of Relativistic Speeds • Interstellar gas in our Galaxy causes small radio sources to “twinkle” (like stars seen in visible light through our atmosphere). • Larger sources do not twinkle (like planets). • Measuring the time when an afterglow stops “twinkling” at radio wavelengths reveals its ...
Emission from dust in galaxies: Metallicity dependence
... Abstract. Infrared (IR) dust emission from galaxies is frequently used as an indicator of star formation rate (SFR). However, the effect of the dust-to-gas ratio (i.e., amount of the dust) on the conversion law from IR luminosity to SFR has not so far been considered. Then, in this paper, we present ...
... Abstract. Infrared (IR) dust emission from galaxies is frequently used as an indicator of star formation rate (SFR). However, the effect of the dust-to-gas ratio (i.e., amount of the dust) on the conversion law from IR luminosity to SFR has not so far been considered. Then, in this paper, we present ...
Activity III: Calibrating Images
... observes the star for a longer period of time, it will gather more light so the star will appear brighter. In most cases, if the exposure time is doubled the amount of light the telescope receives is doubled. One way astronomers use photometry is to measure the brightness variation of an object such ...
... observes the star for a longer period of time, it will gather more light so the star will appear brighter. In most cases, if the exposure time is doubled the amount of light the telescope receives is doubled. One way astronomers use photometry is to measure the brightness variation of an object such ...
A forming disk at z 0.6: collapse of a gaseous disk or major merger
... ) and turbulent phase that is found to be rotating on large spatial scales. We identified two unusual properties of J033241.88-274853.9. (1) The spatial distributions of the ionized gaseous and young stars show a strong decoupling; while almost no stars can be detected in the southern part down to t ...
... ) and turbulent phase that is found to be rotating on large spatial scales. We identified two unusual properties of J033241.88-274853.9. (1) The spatial distributions of the ionized gaseous and young stars show a strong decoupling; while almost no stars can be detected in the southern part down to t ...
A Second Luminous Blue Variable in the Quintuplet Cluster
... of Si ii in absorption (note that the latter would be contaminated by Na i emission), since these lines are expected to be in absorption if the temperature is below 10,000 K. ...
... of Si ii in absorption (note that the latter would be contaminated by Na i emission), since these lines are expected to be in absorption if the temperature is below 10,000 K. ...
Magnetars origin and progenitors with enhanced rotation'
... Magnetars origin and progenitors with enhanced rotation S.B. Popov, M.E. Prokhorov (Sternberg Astronomical Institute) ...
... Magnetars origin and progenitors with enhanced rotation S.B. Popov, M.E. Prokhorov (Sternberg Astronomical Institute) ...
Cosmic distance ladder
The cosmic distance ladder (also known as the extragalactic distance scale) is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are ""close enough"" (within about a thousand parsecs) to Earth. The techniques for determining distances to more distant objects are all based on various measured correlations between methods that work at close distances and methods that work at larger distances. Several methods rely on a standard candle, which is an astronomical object that has a known luminosity.The ladder analogy arises because no one technique can measure distances at all ranges encountered in astronomy. Instead, one method can be used to measure nearby distances, a second can be used to measure nearby to intermediate distances, and so on. Each rung of the ladder provides information that can be used to determine the distances at the next higher rung.