3 research outputs found
COMAP Early Science: VIII. A Joint Stacking Analysis with eBOSS Quasars
We present a new upper limit on the cosmic molecular gas density at z = 2.4 − 3.4 obtained using the first year of observations from the CO Mapping Array Project (COMAP). COMAP data cubes are stacked on the 3D positions of 243 quasars selected from the Extended Baryon Oscillation SpectroscopicSurvey (eBOSS) catalog, yielding a 95% upper limit for flux from CO(1-0) line emission of 0.129 Jykm/s. Depending on the balance of the emission between the quasar host and its environment, this value can be interpreted as an average CO line luminosity L′CO of eBOSS quasars of ≤ 1.26 × 1011 K km pc2s−1, or an average molecular gas density ρH2 in regions of the universe containing a quasar of ≤ 1.52 × 108 M⊙ cMpc−3. The L′ CO upper limit falls among CO line luminosities obtained fromindividually-targeted quasars in the COMAP redshift range, and the ρH2 value is comparable to upper limits obtained from other Line Intensity Mapping (LIM) surveys and their joint analyses. Further, we forecast the values obtainable with the COMAP/eBOSS stack after the full 5-year COMAP Pathfinder survey. We predict that a detection is probable with this method, depending on the CO properties of the quasar sample. Based on the achieved sensitivity, we believe that this technique of stacking LIM data on the positions of traditional galaxy or quasar catalogs is extremely promising, both asa technique for investigating large galaxy catalogs efficiently at high redshift and as a technique for bolstering the sensitivity of LIM experiments, even with a fraction of their total expected survey data
COMAP Early Science: VIII. A Joint Stacking Analysis with eBOSS Quasars
We present a new upper limit on the cosmic molecular gas density at
obtained using the first year of observations from the CO Mapping
Array Project (COMAP). COMAP data cubes are stacked on the 3D positions of 282
quasars selected from the Extended Baryon Oscillation Spectroscopic Survey
(eBOSS) catalog, yielding a 95% upper limit for flux from CO(1-0) line emission
of 0.210 Jy km/s. Depending on the assumptions made, this value can be
interpreted as either an average CO line luminosity of eBOSS
quasars of K km pc s, or an average
molecular gas density in regions of the universe containing
a quasar of M cMpc. The
upper limit falls among CO line luminosities obtained from
individually-targeted quasars in the COMAP redshift range, and the
value is comparable to upper limits obtained from other
Line Intensity Mapping (LIM) surveys and their joint analyses. Further, we
forecast the values obtainable with the COMAP/eBOSS stack after the full 5-year
COMAP Pathfinder survey. We predict that a detection is probable with this
method, depending on the CO properties of the quasar sample. Based on these
achieved sensitivities, we believe that this technique of stacking LIM data on
the positions of traditional galaxy or quasar catalogs is extremely promising,
both as a technique for investigating large galaxy catalogs efficiently at high
redshift and as a technique for bolstering the sensitivity of LIM experiments,
even with a fraction of their total expected survey data.Comment: 15 pages, 8 figures. To be submitted to Ap
COMAP Early Science: VII. Prospects for CO Intensity Mapping at Reionization
We introduce COMAP-EoR, the next generation of the Carbon Monoxide Mapping
Array Project aimed at extending CO intensity mapping to the Epoch of
Reionization. COMAP-EoR supplements the existing 30 GHz COMAP Pathfinder with
two additional 30 GHz instruments and a new 16 GHz receiver. This combination
of frequencies will be able to simultaneously map CO(1--0) and CO(2--1) at
reionization redshifts () in addition to providing a significant
boost to the sensitivity of the Pathfinder. We examine a set of
existing models of the EoR CO signal, and find power spectra spanning several
orders of magnitude, highlighting our extreme ignorance about this period of
cosmic history and the value of the COMAP-EoR measurement. We carry out the
most detailed forecast to date of an intensity mapping cross-correlation, and
find that five out of the six models we consider yield signal to noise ratios
(S/N) for COMAP-EoR, with the brightest reaching a S/N above 400.
We show that, for these models, COMAP-EoR can make a detailed measurement of
the cosmic molecular gas history from , as well as probe the
population of faint, star-forming galaxies predicted by these models to be
undetectable by traditional surveys. We show that, for the single model that
does not predict numerous faint emitters, a COMAP-EoR-type measurement is
required to rule out their existence. We briefly explore prospects for a
third-generation Expanded Reionization Array (COMAP-ERA) capable of detecting
the faintest models and characterizing the brightest signals in extreme detail.Comment: Paper 7 of 7 in series. 19 pages, 10 figures, to be submitted to Ap