A Quick Look at the $3,$GHz Radio Sky I. Source Statistics from the Very Large Array Sky Survey. (arXiv:2102.11753v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Gordon_Y/0/1/0/all/0/1">Yjan A. Gordon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Boyce_M/0/1/0/all/0/1">Michelle M. Boyce</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+ODea_C/0/1/0/all/0/1">Christopher P. O'Dea</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Rudnick_L/0/1/0/all/0/1">Lawrence Rudnick</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Andernach_H/0/1/0/all/0/1">Heinz Andernach</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Vantyghem_A/0/1/0/all/0/1">Adrian N. Vantyghem</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Baum_S/0/1/0/all/0/1">Stefi A. Baum</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bui_J/0/1/0/all/0/1">Jean-Paul Bui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Dionyssiou_M/0/1/0/all/0/1">Mathew Dionyssiou</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sander_I/0/1/0/all/0/1">Isabel Sander</a>
The Very Large Array Sky Survey (VLASS) is observing the entire sky north of
$-40^{circ}$ in the S-band ($2<nu<4,$GHz), with the highest angular
resolution ($2”.5$) of any all-sky radio continuum survey to date. VLASS will
cover its entire footprint over three distinct epochs, the first of which has
now been observed in full. Based on rapidly produced Quick Look images from
this first epoch, we have created a catalog of $1.7times10^{6}$ reliably
detected radio components with $S_{text{peak}}gtrsim1,$mJy/beam. We describe
the production of this catalog and quantify the impact of the limited-quality
Quick Look images on the scientific usability of the resultant data.
Comparisons with independent observations show that flux density measurements
at $S_{text{peak}}gtrsim3,$mJy/beam are systematically underestimated by
$sim10,%$. Components with $S_text{peak}<3,$mJy/beam often have unreliable
flux density measurements. We use this catalog to perform a statistical
analysis of the $nu sim 3,$GHz radio sky. Comparisons with the Faint Images
of the Radio Sky at Twenty cm survey (FIRST) show the typical $1.4-3,$GHz
spectral index to be $alphasim-0.76$. The radio color-color distribution of
both point and extended VLASS components is explored by matching with FIRST and
the LOFAR Two Meter Sky Survey. The VLASS $dN/dS$ is presented and found to be
consistent with previous observations at both $1.4$ and $3,$GHz. The improved
resolution of VLASS relative to FIRST is demonstrated by excess power in the
VLASS two-point correlation function at $thetalesssim 7”$, and by $17,%$
of active galactic nuclei associated with single FIRST component being observed
as multi-component sources by VLASS.
The Very Large Array Sky Survey (VLASS) is observing the entire sky north of
$-40^{circ}$ in the S-band ($2<nu<4,$GHz), with the highest angular
resolution ($2”.5$) of any all-sky radio continuum survey to date. VLASS will
cover its entire footprint over three distinct epochs, the first of which has
now been observed in full. Based on rapidly produced Quick Look images from
this first epoch, we have created a catalog of $1.7times10^{6}$ reliably
detected radio components with $S_{text{peak}}gtrsim1,$mJy/beam. We describe
the production of this catalog and quantify the impact of the limited-quality
Quick Look images on the scientific usability of the resultant data.
Comparisons with independent observations show that flux density measurements
at $S_{text{peak}}gtrsim3,$mJy/beam are systematically underestimated by
$sim10,%$. Components with $S_text{peak}<3,$mJy/beam often have unreliable
flux density measurements. We use this catalog to perform a statistical
analysis of the $nu sim 3,$GHz radio sky. Comparisons with the Faint Images
of the Radio Sky at Twenty cm survey (FIRST) show the typical $1.4-3,$GHz
spectral index to be $alphasim-0.76$. The radio color-color distribution of
both point and extended VLASS components is explored by matching with FIRST and
the LOFAR Two Meter Sky Survey. The VLASS $dN/dS$ is presented and found to be
consistent with previous observations at both $1.4$ and $3,$GHz. The improved
resolution of VLASS relative to FIRST is demonstrated by excess power in the
VLASS two-point correlation function at $thetalesssim 7”$, and by $17,%$
of active galactic nuclei associated with single FIRST component being observed
as multi-component sources by VLASS.
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