The Orbital Evolution of Gas Giant Planets around Giant Stars (2009)
Recent surveys have revealed a lack of close-in planets around evolved stars more massive than 1.2 Msun. Such planets are common around solar-mass stars. We have calculated the orbital evolution of...
Type II Supernovae as Probes of Cosmology (2009)
Poznanski, Dovi, Baron, Eddie, Blondin, Stephane, Bloom, Joshua S., D'Andrea, Christopher B., Della Valle, Massimo, ...
- Constraining the cosmological parameters and understanding Dark Energy have tremendous implications for the nature of the Universe and its physical laws. - The pervasive limit of systematic...
The WFC3 Galactic Bulge Treasury Program: A First Look at Resolved Stellar Population Tools (2008)
Brown, Thomas M., Sahu, Kailash, Zoccali, Manuela, Renzini, Alvio, Ferguson, Henry C., Anderson, Jay, ...
[Abridged] When WFC3 is installed on HST, the community will have powerful new tools for investigating resolved stellar populations. The WFC3 Galactic Bulge Treasury program will obtain deep imaging...
Stellar Proper Motions in the Galactic Bulge from deep HST ACS/WFC Photometry (2008)
Clarkson, Will, Sahu, Kailash, Anderson, Jay, Smith, T. Ed., Brown, Thomas M., Rich, R. Michael, ...
We present stellar proper motions in the Galactic bulge from the Sagittarius Window Eclipsing Extrasolar Search (SWEEPS) project using ACS/WFC on HST. Proper motions are extracted for more than...
Planets in the Galactic Bulge: Results from the SWEEPS Project (2007)
Sahu, Kailash C., Casertano, Stefano, Valenti, Jeff, Bond, Howard E., Brown, Thomas M., Smith, T. Ed, ...
The exoplanets discovered so far have been mostly around relatively nearby and bright stars. As a result, the host stars are mostly (i) in the Galactic disk, (ii) relatively massive, and (iii)...
The Swallowing of Planets by Giant Stars (2007)
We present simulations of the accretion of a massive planet or brown dwarf by an AGB star. In our scenario, close planets will be engulfed by the star, spiral-in and be dissipated in the...
The Accretion of Brown Dwarfs and Planets by Giant Stars (2007)
We study the response of the structure of an asymptotic giant branch (AGB) star to the accretion of a brown dwarf or planet in its interior. In particular, we examine the case in which the brown...
Is the Bardeen-Petterson effect responsible for the warping and precession in NGC 4258? (2007)
Caproni, Anderson, Abraham, Zulema, Livio, Mario, Cuesta, Herman J. Mosquera
Strong evidence for the presence of a warped Keplerian accretion disc in NGC4258 (M 106) has been inferred from the kinematics of water masers detected at sub-parsec scales. Assuming a power-law...
Can Planets survive Stellar Evolution? (2007)
We study the survival of gas planets around stars with masses in the range 1-5 Msun, as these stars evolve off the Main Sequence. We show that planets with masses smaller than one Jupiter mass do not...
978-84-344-5324-1
La proporción áurea : la historia de 'phi', el número más enigmático del mundo (2007)
978-84-344-4495-X
Discovery of thirteen novae candidates in M87 (2006)
Madrid, Juan P., Sparks, William B., Ferguson, Henry C., Livio, Mario, Macchetto, Duccio
We have made thirteen positive identifications of near-ultraviolet (NUV) transient sources in the giant elliptical galaxy M87 using the Space Telescope Imaging Spectrograph (STIS) on board the Hubble...
Riess, Adam G., Strolger, Louis-Gregory, Casertano, Stefano, Ferguson, Henry C., Mobasher, Bahram, Gold, Ben, ...
We have discovered 21 new Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to trace the history of cosmic expansion over the last 10 billion years. These objects,...
Transiting extrasolar planetary candidates in the Galactic bulge (2006)
Sahu, Kailash C., Casertano, Stefano, Bond, Howard E., Valenti, Jeff, Smith, T. Ed, Minniti, Dante, ...
More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to the reflex motions of their host stars, and more recently...
Warping and precession in galactic and extragalactic accretion disks (2006)
Caproni, Anderson, Livio, Mario, Abraham, Zulema, Cuesta, Herman J. Mosquera
The Bardeen-Petterson general relativistic effect has been suggested as the mechanism responsible for precession in some accretion disk systems. Here we examine separately four mechanisms...
Future measurements of the nature of dark energy using Type Ia supernovae will require a precise characterization of systematic sources of error. Evolutionary effects remain the most uncertain...
McGowan, Katherine E., Charles, Phil A., Blustin, Alexander J., Livio, Mario, O'Donoghue, Darragh, Heathcote, Bernard
The highly luminous (> 10^37 erg s^-1) supersoft X-ray sources (SSS) are believed to be Eddington limited accreting white dwarfs undergoing surface hydrogen burning. The current paradigm for SSS...
Li, Weidong, Van Dyk, Schuyler D., Filippenko, Alexei V., Cuillandre, Jean-Charles, Jha, Saurabh, Bloom, Joshua S., ...
The stars that end their lives as supernovae (SNe) have been directly observed in only a handful of cases, due mainly to the extreme difficulty in identifying them in images obtained prior to the SN...
High Redshift Supernova Rates (2004)
Dahlen, Tomas, Strolger, Louis-Gregory, Riess, Adam G., Mobasher, Bahram, Chary, Ranga-Ram, Conselice, Christopher J., ...
We use a sample of 42 supernovae detected with the Advanced Camera for Surveys on-board the Hubble Space Telescope as part of the Great Observatories Origins Deep Survey to measure the rate of core...
Limits on the Optical Brightness of the Epsilon Eridani Dust Ring (2004)
Proffitt, Charles, Sahu, Kailash, Livio, Mario, Krist, John, Calzetti, Daniela, Gilliland, Ron, ...
The STIS/CCD camera on the {\em Hubble Space Telescope (HST)} was used to take deep optical images near the K2V main-sequence star $\epsilon$ Eridani in an attempt to find an optical counterpart of...
Orbital capture of stars by a massive black hole via exchanges with compact remnants (2004)
We propose a dynamical mechanism for capturing stars around a massive black hole (MBH), which is based on the accumulation there of a very dense cluster of compact stellar remnants. This study is...
Riess, Adam G., Strolger, Louis-Gregory, Tonry, John, Casertano, Stefano, Ferguson, Henry C., Mobasher, Bahram, ...
We have discovered 16 Type Ia supernovae (SNe Ia) with the Hubble Space Telescope (HST) and have used them to provide the first conclusive evidence for cosmic deceleration that preceded the current...
The Size Evolution of High Redshift Galaxies (2003)
Ferguson, Henry C., Dickinson, Mark, Giavalisco, Mauro, Kretchmer, Claudia, Ravindranath, Swara, Idzi, Rafal, ...
Hubble Space Telescope images of high-redshift galaxies selected via color and photometric redshifts are used to examine the size and axial-ratio distribution of galaxies as a function of redshift at...
Structure and Evolution of Starburst and Normal Galaxies (2003)
Mobasher, Bahram, Jogee, Shardha, Dahlen, Tomas, De Mello, Duilia, Conselice, Christopher, Grogin, Norman, ...
We study the rest-frame morphology and structural properties of optically selected starburst galaxies at redshift z < 1, using multi-waveband (BViz) high resolution images taken by the Advanced...
Have the Elusive Progenitors of Supernovae Type Ia Been Discovered? (2003)
The recent detection of H-alpha emission in the supernova Type Ia SN 2002ic could be taken to mean that the elusive progenitor systems of Type Ia supernovae have finally been identified. At first...
The Disk-Jet Connection in Microquasars and AGN (2003)
Livio, Mario, Pringle, J. E., King, A. R.
We propose a new model for the disk-jet connection in black hole x-ray transients and active galactic nuclei. In our model, the inner part of the accretion disk around the central black hole switches...
The world according to the Hubble Space Telescope (2003)
The Hubble Space Telescope (HST), in its thirteen years of operation, has allowed us to observe properties of the universe humans have been able, until very recently, to probe only with their...
The Epoch of Reionization in Models with Reduced Small Scale Power (2003)
Somerville, Rachel S., Bullock, James S., Livio, Mario
Reducing the power on small scales relative to the `standard' LCDM model alleviates a number of possible discrepancies with observations, and is favored by the recent analysis of WMAP plus galaxy and...
Star Formation at the Twilight of the Dark Ages: Which Stars Reionized the Universe? (2003)
Somerville, Rachel S., Livio, Mario
We calculate the global star formation rate density (SFRD) from z ~ 30-3 using a semi-analytic model incorporating the hierarchical assembly of dark matter halos, gas cooling via atomic hydrogen,...
I examine some recent findings in cosmology and their potential implications for the emergence of life in the universe. In particular, I discuss the requirements for carbon-based life, anthropic...
Will Jets Identify the Progenitors of Type Ia Supernovae? (2002)
Livio, Mario, Riess, Adam, Sparks, William
We use the fact that a Type Ia supernova has been serendipitously discovered near the jet of the active galaxy 3C 78 to examine the question of whether jets can enhance accretion onto white dwarfs....
The Effects of Planets and Brown Dwarfs on Stellar Rotation and Mass-Loss (2002)
We examine the effects of the engulfment of planets by giant stars on the evolution of late-type stars. We show that the rate at which dynamo-generated magnetic energy is being released exceeds 10%...
Predictions for the frequency and orbital radii of massive extrasolar planets (2002)
Armitage, Philip J., Livio, Mario, Lubow, S. H., Pringle, J. E.
We investigate the migration of massive extrasolar planets due to gravitational interaction with a viscous protoplanetary disc. We show that a model in which planets form at 5 AU at a constant rate,...
The Unique History of the Globular Cluster Omega Centauri (2002)
Gnedin, Oleg Y., Zhao, HongSheng, Pringle, J. E., Fall, S. Michael, Livio, Mario, Meylan, Georges
Using current observational data and simple dynamical modeling, we demonstrate that Omega Cen is not special among the Galactic globular clusters in its ability to produce and retain the heavy...
Structure, Evolution and Nucleosynthesis of Primordial Stars (2002)
Siess, Lionel, Livio, Mario, Lattanzio, John
(abridge version) The evolution of population III stars (Z=0) is followed from the pre-main sequence phase up to the AGB phase for intermediate-mass stars and up to C ignition in more massive...
Proper motions in the knotty, bipolar jet in Henize 2-90 (2002)
Nyman, Lars-Ake, Tingay, Steven J., Brillant, Stephane, Grebel, Eva K., Brandner, Wolfgang, Livio, Mario, ...
Abstract not available.
Proper motions in the knotty, bipolar jet in Henize 2-90 (2002)
Nyman, Lars-Ake, Tingay, Steven J., Brillant, Stephane, Grebel, Eva K., Brandner, Wolfgang, Livio, Mario, ...
Abstract not available.
Proper motions in the knotty, bipolar jet in Henize 2-90 (2002)
Nyman, Lars-Ake, Tingay, Steven J., Brillant, Stephane, Grebel, Eva K., Brandner, Wolfgang, Livio, Mario, ...
Abstract not available.
Proper motions in the knotty, bipolar jet in Henize 2-90 (2002)
Nyman, Lars-Ake, Tingay, Steven J., Brillant, Stephane, Grebel, Eva K., Brandner, Wolfgang, Livio, Mario, ...
Abstract not available.
Proper motions in the knotty, bipolar jet in Henize 2-90 (2002)
Nyman, Lars-Ake, Tingay, Steven J., Brillant, Stephane, Grebel, Eva K., Brandner, Wolfgang, Livio, Mario, ...
Abstract not available.
Tidal scattering of stars on supermassive black holes in galactic centers (2001)
Some of the mass that feeds the growth of a massive black hole (BH) in a galactic center is supplied by tidal disruption of stars that approach it on unbound, low angular momentum orbits. For each...
The large-scale ionised outflow of CH Cygni (2001)
Corradi, Romano L. M., Munari, Ulisse, Livio, Mario, Mampaso, Antonio, Goncalves, Denise R., Schwarz, Hugo E.
HST and ground-based [OII} and [NII] images obtained from 1996 to 1999 reveal the existence of a ionised optical nebula around the symbiotic binary CH Cyg extending out to 5000 A.U. from the central...
Panel Discussion on Observing Simulations and Simulating Observations (2001)
Hut, Piet, Cool, Adrienne, Bailyn, Charles, McMillan, Steve, Livio, Mario, Shara, Mike
N-body simulations of star cluster evolution have reached a high degree of realism, by incorporating more and more elements of stellar dynamics, stellar evolution, and hydrodynamics. At the end of...
Riess, Adam G., Nugent, Peter E., Schmidt, Brian P., Tonry, John, Dickinson, Mark, Gilliland, Ronald L., ...
We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift of ~1.7, the farthest SN observed to date. SN 1997ff, was discovered in a repeat observation by the HST of...
Eccentric extrasolar planets from resonant Saturn mass companions (2001)
Armitage, Philip J., Livio, Mario, Lubow, S. H., Pringle, J. E.
Withdrawn in current form.
Riess, Adam G., Nugent, Peter E., Schmidt, Brian P., Tonry, John, Dickinson, Mark, Gilliland, Ronald L., ...
We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift of approximately 1.7, the farthest SN observed to date. The supernova, SN 1997, was discovered in a repeat...
Space Telescope Science Institute Symposium : The Dark Universe : Matter, Energy, and Gravity (2001)
Episodic accretion in magnetically layered protoplanetary discs (2001)
Armitage, Philip J., Livio, Mario, Pringle, J. E.
We study protoplanetary disc evolution assuming that angular momentum transport is driven by gravitational instability at large radii, and magnetohydrodynamic (MHD) turbulence in the hot inner...
Adam G. Riess, Peter E. Nugent, Ronald L. Gilliland, Brian P. Schmidt, John Tonry, Mark Dickinson, ...
We present photometric observations of an apparent Type Ia supernova (SN Ia) at a redshift of D1.7, the farthest SN observed to date. The supernova, SN 1997+, was discovered in a repeat observation...
The "Twin Jet" Planetary Nebula M2-9 (2000)
We present a model for the structure, temporal behavior, and evolutionary status of the bipolar nebula M2-9. According to this model the system consists of an AGB or post-AGB star and a hot white...
Launching of jets and the vertical structure of accretion disks (2000)
Ogilvie, Gordon I., Livio, Mario
The launching of magnetohydrodynamic outflows from accretion disks is considered. We formulate a model for the local vertical structure of a thin disk threaded by a poloidal magnetic field of dipolar...
Hubble Space Telescope Observations of the Planetary Nebula K648 in the Globular Cluster M15 (2000)
Alves, David R., Bond, Howard E., Livio, Mario
We have obtained observations of the planetary nebula K648 in the Galactic globular cluster M15 with the Hubble Space Telescope's WFPC2 camera, covering an interval of 7 days. The frames provide both...
Type Ia Supernovae and their implications for cosmology (2000)
Models for Type Ia Supernovae (SNe Ia) are reviewed. It is shown that there are strong reasons to believe that most SNe Ia represent thermonuclear disruptions of C-O white dwarfs, when these white...
The Formation and Role of Vortices in Protoplanetary Disks (1999)
We carry out a two-dimensional, compressible, simulation of a disk, including dust particles, to study the formation and role of vortices in protoplanetary disks. We find that anticyclonic vortices...
Radio loud and radio quiet active galactic nuclei (1999)
Xu, Chun, Livio, Mario, Baum, Stefi
Also archived in: arXiv: astro-ph/9905322 v1 25 May 1999
Radio loud and radio quiet active galactic nuclei (1999)
Xu, Chun, Livio, Mario, Baum, Stefi
Also archived in: arXiv: astro-ph/9905322 v1 25 May 1999
The Ages of Pre-main-sequence Stars (1999)
Tout, Christopher A., Livio, Mario, Bonnell, Ian A.
The position of pre-main-sequence or protostars in the Hertzsprung--Russell diagram is often used to determine their mass and age by comparison with pre-main-sequence evolution tracks. On the...
The cosmological constant and the time of its dominance (1999)
Garriga, Jaume, Livio, Mario, Vilenkin, Alexander
We explore a model in which the cosmological constant $\Lambda$ and the density contrast at the time of recombination $\sigma_{rec}$ are random variables, whose range and {\it a priori} probabilities...
Black hole formation via hypercritical accretion during common envelope evolution (1999)
Armitage, Philip J., Livio, Mario
Neutron stars inspiralling into a stellar envelope can accrete at rates vastly exceeding the Eddington limit if the flow develops pressures high enough to allow neutrinos to radiate the released...
Radio Loud and Radio Quiet Active Galactic Nuclei (1999)
Xu, Chun, Livio, Mario, Baum, Stefi A.
We generated a sample of 409 AGNs for which both the radio luminosity at 5 GHz and the line luminosity in [OIII] 5007 have been measured. The radio luminosity spans a range of ten orders of...
This paper extends our previous study of planet/brown dwarf accretion by giant stars to solar mass stars located on the red giant branch. The model assumes that the planet is dissipated at the bottom...
Fruchter, Andrew S., Thorsett, S. E., Metzger, Mark R., Sahu, Kailash C., Petro, Larry, Livio, Mario, ...
We report on HST and Palomar optical images of the field of GRB 990123, obtained on 8 and 9 February 1999. We find that the optical transient (OT) associated with GRB 990123 is located on an...
Vortices in Protoplanetary Disks (1999)
We use a high order accuracy spectral code to carry out two-dimensional time-dependent numerical simulations of vortices in accretion disks. In particular, we examine the stability and the life time...
The Accretion of Brown Dwarfs and Planets by Giant Stars -- I. AGB Stars (1998)
We study the response of the structure of an asymptotic giant branch (AGB) star to the accretion of a brown dwarf or planet in its interior. In particular, we examine the case in which the brown...
On the non-linear hydrodynamic stability of thin Keplerian disks (1998)
The non-linear hydrodynamic stability of thin, compressible, Keplerian disks is studied on the large two-dimensional compressible scale, using a high-order accuracy spectral method. We show that...
Accretion Disks: Limit Cycles and Instabilities (1998)
The existing disk instability model for dwarf nova eruptions is reviewed, in the light of recent progress in the understanding of angular momentum transport in accretion disks. It is proposed that...
Supernova 1987A: Rotation and a Binary Companion (1998)
Collins, T. J. B., Frank, Adam, Bjorkman, J. E., Livio, Mario
In this paper we provide a possible link between the structure of the bipolar nebula surrounding SN1987A and the properties of its progenitor star. A Wind Blwon Bubble (WBB) scenario is emplyed, in...
Does the Fine Structure Constant Really Vary in Time? (1998)
Livio, Mario, Stiavelli, Massimo
We discuss how laboratory experiments can be used to place constraints on possible variations of the fine structure constant alpha in the observationally relevant redshift interval z ~= 0 - 5, within...
How Rare Are Extraterrestrial Civilizations and When Did They Emerge? (1998)
It is shown that, contrary to an existing claim, the near equality between the lifetime of the sun and the timescale of biological evolution on earth does not necessarily imply that extraterrestrial...
The Swallowing of Planets by Giant Stars (1998)
We present simulations of the accretion of a massive planet or brown dwarf by an AGB star. In our scenario, close planets will be engulfed by the star, spiral-in and be dissipated in the ``accretion...
On Jet Features in the Optical Spectra of Cataclysmic Variables (1998)
Knigge, Christian, Livio, Mario
Blue- and red-shifted Hydrogen and Helium satellite recombination lines have recently been discovered in the optical spectra of at least two supersoft X-ray sources (SSSs), RX J0513-069 and RX...
Close Binary White Dwarf Systems: Numerous New Detections and Their Interpretation (1998)
Saffer, Rex A., Livio, Mario, Yungelson, Lev R.
We describe radial velocity observations of a large sample of apparently single white dwarfs (WDs), obtained in a long-term effort to discover close, double-degenerate (DD) pairs which might comprise...
HST/STIS Observations of the Optical Counterpart to GRB 970228 (1998)
Fruchter, Andrew S., Pian, Elena, Thorsett, Stephen E., Gonzalez, Rosa, Sahu, Kailash C., Mutchler, Max, ...
We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made on 4~September~1997 using the STIS CCD on the Hubble Space Telescope. The unresolved counterpart is...
The decay of optical emission from the Gamma-Ray Burst GRB 970228 (1997)
Galama, Titus J., Groot, Paul J., Van Paradijs, Jan, Kouveliotou, Chryssa, Sahu, Kailash C., Livio, Mario, ...
We present the R_c band light curve of the optical transient (OT) associated with GRB970228, based on re-evaluation of existing photometry. Data obtained until April 1997 suggested a slowing down of...
On the difficulty of launching an outflow from an accretion disk (1997)
Ogilvie, Gordon I., Livio, Mario
We solve for the local vertical structure of a thin accretion disk threaded by a poloidal magnetic field. The angular velocity deviates from the Keplerian value as a result of the radial Lorentz...
The Gamma Ray Bursts GRB970228 and GRB970508: What Have We Learnt? (1997)
Livio, Mario, Sahu, Kailash C., Petro, Larry, Fruchter, Andrew, Pian, Elena, Macchetto, F. Duccio, ...
We examine what we regard as key observational results on GRB 970228 and GRB 970508 and show that the accumulated evidence strongly suggests that gamma-ray bursts (GRBs) are cosmological fireballs....
Type Ia Supernovae: An Examination of Potential Progenitors and the Redshift Distribution (1997)
Yungelson, Lev R., Livio, Mario
We examine the possibility that supernovae type Ia (SN Ia) are produced by white dwarfs accreting from Roche-lobe filling evolved companions, under the assumption that a strong optically thick...
Hydrodynamics of the stream-disk impact in interacting binaries (1997)
Armitage, Philip J., Livio, Mario
We use hydrodynamic simulations to provide quantitative estimates of the effects of the impact of the accretion stream on disks in interacting binaries. For low accretion rates, efficient radiative...
The Properties of X-Ray and Optical Light Curves of X-Ray Novae (1997)
Chen, Wan, Shrader, C. R., Livio, Mario
We have collected the available data from the literature and from public data archives covering the past two decades for the long-term X-ray and optical light curves of X-ray nova (XN) outbursts, and...
Observations of GRB 970228 and GRB 970508, and the Neutron-Star Merger Model (1997)
Sahu, Kailash C., Livio, Mario, Petro, Larry, Bond, Howard E., Macchetto, F. Duccio, Galama, Titus J., ...
We present the discovery observations for the optical counterpart of the $\gamma$-ray burster GRB 970508 and discuss its light curve in the context of the fireball model. We analyze the HST data for...
Sahu, Kailash C., Livio, Mario, Petro, Larry, Macchetto, F. Duccio, Van Paradijs, Jan, Kouveliotou, Chryssa, ...
Although more than 2,000 astronomical gamma-ray bursts (GRBs) have been detected, and numerous models proposed to explain their occurrence, they have remained enigmatic owing to the lack of an...
On the Formation and Evolution of Common Envelope Systems (1995)
Rasio, Frederic A., Livio, Mario
We discuss the formation of a common envelope system following dynamically unstable mass transfer in a close binary, and the subsequent dynamical evolution and final fate of the envelope. We base our...
RAYLEIGH-TAYLOR CONVECTIVE OVERTURN AS A POSSIBLE SOLUTION TO THE SUPERNOVA PUZZLE (1980)
Livio, Mario, Robert Buchler, J.
Strong neutronization above the neutrinosphere produces a convectively unstable gradient of the electron to baryon ratio Ye. An l = 2 Rayleigh-Taylor overturn of the whole core is expected to ensue....
RAYLEIGH-TAYLOR CONVECTIVE OVERTURN AS A POSSIBLE SOLUTION TO THE SUPERNOVA PUZZLE (1980)
Livio, Mario, Robert Buchler, J.
Strong neutronization above the neutrinosphere produces a convectively unstable gradient of the electron to baryon ratio Ye. An l = 2 Rayleigh-Taylor overturn of the whole core is expected to ensue....
RAYLEIGH-TAYLOR CONVECTIVE OVERTURN AS A POSSIBLE SOLUTION TO THE SUPERNOVA PUZZLE (1980)
Livio, Mario, Robert Buchler, J.
Strong neutronization above the neutrinosphere produces a convectively unstable gradient of the electron to baryon ratio Ye. An l = 2 Rayleigh-Taylor overturn of the whole core is expected to ensue....