scholarly journals Seeing-limited Imaging Sky Surveys—Small versus Large Telescopes

2020 ◽  
Vol 132 (1018) ◽  
pp. 125004
Author(s):  
E. O. Ofek ◽  
S. Ben-Ami
Keyword(s):  
Sky Surveys ◽  
Large Telescopes

Seti Figure of Merit

1997 ◽  
Vol 161 ◽  
pp. 711-717 ◽  
Author(s):  
John W. Dreher ◽  
D. Kent Cullers
Keyword(s):  
Figure Of Merit ◽  
Qualitative Difference ◽  
Current Generation ◽  
Detection Range ◽  
Sky Surveys ◽  
Independent Observations ◽  
Good For

AbstractWe develop a figure of merit for SETI observations which is anexplicitfunction of the EIRP of the transmitters, which allows us to treat sky surveys and targeted searches on the same footing. For each EIRP, we calculate the product of terms measuring the number of stars within detection range, the range of frequencies searched, and the number of independent observations for each star. For a given set of SETI observations, the result is a graph of merit versus transmitter EIRP. We apply this technique to several completed and ongoing SETI programs. The results provide a quantitative confirmation of the expected qualitative difference between sky surveys and targeted searches: the Project Phoenix targeted search is good for finding transmitters in the 109to 1014W range, while the sky surveys do their best at higher powers. Current generation optical SETI is not yet competitive with microwave SETI.

The First Galaxies in the Universe

2013 ◽  
Author(s):  
Abraham Loeb ◽  
Steven R. Furlanetto
Keyword(s):  
Galaxy Evolution ◽  
Big Bang ◽  
First Stars ◽  
Distant Galaxies ◽  
Formation And Evolution ◽  
Early Galaxies ◽  
First Galaxies ◽  
Large Telescopes ◽  
New Generation ◽  
The Big Bang

This book provides a comprehensive, self-contained introduction to one of the most exciting frontiers in astrophysics today: the quest to understand how the oldest and most distant galaxies in our universe first formed. Until now, most research on this question has been theoretical, but the next few years will bring about a new generation of large telescopes that promise to supply a flood of data about the infant universe during its first billion years after the big bang. This book bridges the gap between theory and observation. It is an invaluable reference for students and researchers on early galaxies. The book starts from basic physical principles before moving on to more advanced material. Topics include the gravitational growth of structure, the intergalactic medium, the formation and evolution of the first stars and black holes, feedback and galaxy evolution, reionization, 21-cm cosmology, and more.

scholarly journals Hunting for intermediate-mass black holes in globular clusters: an astrometric study of NGC 6441

2021 ◽  
Vol 503 (1) ◽  
pp. 1490-1506
Author(s):  
Maximilian Häberle ◽  
Mattia Libralato ◽  
Andrea Bellini ◽  
Laura L Watkins ◽  
Jörg-Uwe Pott ◽  
...  
Keyword(s):  
Globular Clusters ◽  
Velocity Dispersion ◽  
Angular Resolution ◽  
Hubble Space Telescope ◽  
High Mass ◽  
High Angular Resolution ◽  
Stellar Kinematics ◽  
Intermediate Mass ◽  
The Core ◽  
Large Telescopes

ABSTRACT We present an astrometric study of the proper motions (PMs) in the core of the globular cluster NGC 6441. The core of this cluster has a high density and observations with current instrumentation are very challenging. We combine ground-based, high-angular-resolution NACO@VLT images with Hubble Space Telescope ACS/HRC data and measure PMs with a temporal baseline of 15 yr for about 1400 stars in the centremost 15 arcsec of the cluster. We reach a PM precision of ∼30 µas yr−1 for bright, well-measured stars. Our results for the velocity dispersion are in good agreement with other studies and extend already existing analyses of the stellar kinematics of NGC 6441 to its centremost region never probed before. In the innermost arcsecond of the cluster, we measure a velocity dispersion of (19.1 ± 2.0) km s−1 for evolved stars. Because of its high mass, NGC 6441 is a promising candidate for harbouring an intermediate-mass black hole (IMBH). We combine our measurements with additional data from the literature and compute dynamical models of the cluster. We find an upper limit of $M_{\rm IMBH} \lt 1.32 \times 10^4\, \textrm{M}_\odot$ but we can neither confirm nor rule out its presence. We also refine the dynamical distance of the cluster to $12.74^{+0.16}_{-0.15}$ kpc. Although the hunt for an IMBH in NGC 6441 is not yet concluded, our results show how future observations with extremely large telescopes will benefit from the long temporal baseline offered by existing high-angular-resolution data.

Ultrastable high-resolution spectrographs for large telescopes

1998 ◽  
Author(s):  
Francisco Diego ◽  
Ian A. Crawford ◽  
David D. Walker
Keyword(s):  
High Resolution ◽  
Large Telescopes

Spectropolarimetry with Extremely Large Telescopes

2005 ◽  
Vol 1 (S232) ◽  
pp. 248-254 ◽  
Author(s):  
Dietrich Baade ◽  
Lifan Wang ◽  
Swetlana Hubrig ◽  
Ferdinando Patat
Keyword(s):  
Large Telescopes

scholarly journals FINDING, CHARACTERIZING, AND CLASSIFYING VARIABLE SOURCES IN MULTI-EPOCH SKY SURVEYS: QSOs AND RR LYRAE IN PS1 3πDATA

2016 ◽  
Vol 817 (1) ◽  
pp. 73 ◽  
Author(s):  
Nina Hernitschek ◽  
Edward F. Schlafly ◽  
Branimir Sesar ◽  
Hans-Walter Rix ◽  
David W. Hogg ◽  
...  
Keyword(s):  
Sky Surveys ◽  
Rr Lyrae

scholarly journals Galaxy Evolution Studies with the SPace IR Telescope for Cosmology and Astrophysics (SPICA): The Power of IR Spectroscopy

2017 ◽  
Vol 34 ◽  
Author(s):  
L. Spinoglio ◽  
A. Alonso-Herrero ◽  
L. Armus ◽  
M. Baes ◽  
J. Bernard-Salas ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Formation Rate ◽  
Cosmic Time ◽  
Galactic Nuclei ◽  
Large Area ◽  
Radiation Fields ◽  
James Webb Space Telescope ◽  
Large Telescopes

AbstractIR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.

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