233 research outputs found
Rapid Star Formation in the Presence of Active Galactic Nuclei
Recent observations reveal galaxies in the early Universe (2<z<6.4) with
large reservoirs of molecular gas and extreme star formation rates. For a very
large range of sources, a tight relationship exists between star formation rate
and the luminosity of the HCN J=1-0 spectral line, but sources at redshifts of
z~2 and beyond do not follow this trend. The deficit in HCN is conventionally
explained by an excess of infrared (IR) radiation due to active galactic nuclei
(AGN). We show in this letter not only that the presence of AGN cannot account
for the excess of IR over molecular luminosity, but also that the observed
abundance of HCN is in fact consistent with a population of stars forming from
near-primordial gas.Comment: 4 pages, 1 figure. Accepted by the Astrophysical Journal Letter
Morphology in the Era of Large Surveys
The study of galaxies has changed dramatically over the past few decades with
the advent of large-scale astronomical surveys. These large collaborative
efforts have made available high-quality imaging and spectroscopy of hundreds
of thousands of systems, providing a body of observations which has
significantly enhanced our understanding not only of cosmology and large-scale
structure in the universe but also of the astrophysics of galaxy formation and
evolution. Throughout these changes, one thing that has remained constant is
the role of galaxy morphology as a clue to understanding galaxies. But
obtaining morphologies for large numbers of galaxies is challenging; this
topic, "Morphology in the era of large surveys", was the subject of a recent
discussion meeting at the Royal Astronomical Society, and this "Astronomy and
Geophysics" article is a report on that meeting.Comment: Meeting Report article published in the October 2013 issue of the
Royal Astronomical Society journal Astronomy and Geophysics. 4 page pdf with
colour image
Galaxy Zoo: Morphological Classification and Citizen Science
We provide a brief overview of the Galaxy Zoo and Zooniverse projects,
including a short discussion of the history of, and motivation for, these
projects as well as reviewing the science these innovative internet-based
citizen science projects have produced so far. We briefly describe the method
of applying en-masse human pattern recognition capabilities to complex data in
data-intensive research. We also provide a discussion of the lessons learned
from developing and running these community--based projects including thoughts
on future applications of this methodology. This review is intended to give the
reader a quick and simple introduction to the Zooniverse.Comment: 11 pages, 1 figure; to be published in Advances in Machine Learning
and Data Mining for Astronom
Citizen Science: Contributions to Astronomy Research
The contributions of everyday individuals to significant research has grown
dramatically beyond the early days of classical birdwatching and endeavors of
amateurs of the 19th century. Now people who are casually interested in science
can participate directly in research covering diverse scientific fields.
Regarding astronomy, volunteers, either as individuals or as networks of
people, are involved in a variety of types of studies. Citizen Science is
intuitive, engaging, yet necessarily robust in its adoption of sci-entific
principles and methods. Herein, we discuss Citizen Science, focusing on fully
participatory projects such as Zooniverse (by several of the au-thors CL, AS,
LF, SB), with mention of other programs. In particular, we make the case that
citizen science (CS) can be an important aspect of the scientific data analysis
pipelines provided to scientists by observatories.Comment: 12 pages, 2 figure
Galaxy Zoo: an independent look at the evolution of the bar fraction over the last eight billion years from HST-COSMOS
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