We combine recent simulation work on the SFR-C ii correlation at high redshift with empirical modeling of the galaxy-halo connection (via UniverseMachine) to forecast C ii auto power spectra from z ∼ ...4 to z ∼ 8. We compare these to sensitivities realistically expected from various instruments expected to come online in the next decade. If the predictions of our model are correct, C ii should be detectable up to z ∼ 6 in this generation of surveys, but detecting C ii past the end of reionization will require a generational leap in line-intensity survey capabilities.
The early Universe was dust-rich and extremely hot Viero, Marco P; Sun, Guochao; Chung, Dongwoo T ...
Monthly notices of the Royal Astronomical Society. Letters,
10/2022, Volume:
516, Issue:
1
Journal Article
Peer reviewed
Open access
ABSTRACT
We investigate the dust properties and star-formation signature of galaxies in the early Universe by stacking 111 227 objects in the recently released COSMOS catalogue on maps at wavelengths ...bracketing the peak of warmed dust emission. We find an elevated far-infrared luminosity density to redshift 8, indicating abundant dust in the early Universe. We further find an increase of dust temperature with redshift, reaching $100\pm 12\,\mathrm{ K}$ at $\mathit{z}$ ∼ 7, suggesting either the presence of silicate rich dust originating from Population ii stars, or sources of heating beyond simply young hot stars. Lastly, we try to understand how these objects have been missed in previous surveys, and how to design observations to target them. All code, links to the data, and instructions to reproduce this research in full are located at https://github.com/marcoviero/simstack3/.
COMAP Early Science. I. Overview Cleary, Kieran A.; Borowska, Jowita; Breysse, Patrick C. ...
The Astrophysical journal,
07/2022, Volume:
933, Issue:
2
Journal Article
Peer reviewed
Open access
Abstract
The CO Mapping Array Project (COMAP) aims to use line-intensity mapping of carbon monoxide (CO) to trace the distribution and global properties of galaxies over cosmic time, back to the ...Epoch of Reionization (EoR). To validate the technologies and techniques needed for this goal, a Pathfinder instrument has been constructed and fielded. Sensitive to CO(1–0) emission from
z
= 2.4–3.4 and a fainter contribution from CO(2–1) at
z
= 6–8, the Pathfinder is surveying 12 deg
2
in a 5 yr observing campaign to detect the CO signal from
z
∼ 3. Using data from the first 13 months of observing, we estimate
P
CO
(
k
) = −2.7 ± 1.7 × 10
4
μ
K
2
Mpc
3
on scales
k
= 0.051 −0.62 Mpc
−1
, the first direct three-dimensional constraint on the clustering component of the CO(1–0) power spectrum. Based on these observations alone, we obtain a constraint on the amplitude of the clustering component (the squared mean CO line temperature bias product) of
Tb
2
<
49
μ
K
2
, nearly an order-of-magnitude improvement on the previous best measurement. These constraints allow us to rule out two models from the literature. We forecast a detection of the power spectrum after 5 yr with signal-to-noise ratio (S/N) 9–17. Cross-correlation with an overlapping galaxy survey will yield a detection of the CO–galaxy power spectrum with S/N of 19. We are also conducting a 30 GHz survey of the Galactic plane and present a preliminary map. Looking to the future of COMAP, we examine the prospects for future phases of the experiment to detect and characterize the CO signal from the EoR.
Abstract
Line-intensity mapping observations will find fluctuations of integrated line emission are attenuated by varying degrees at small scales due to the width of the line emission profiles. This ...attenuation may significantly impact estimates of astrophysical or cosmological quantities derived from measurements. We consider a theoretical treatment of the effect of line broadening on both the clustering and shot-noise components of the power spectrum of a generic line-intensity power spectrum using a halo model. We then consider possible simplifications to allow easier application in analysis, particularly in the context of inferences that require numerous, repeated, fast computations of model line-intensity signals across a large parameter space. For the CO Mapping Array Project and the CO(1–0) line-intensity field at
z
∼ 3 serving as our primary case study, we expect a ∼10% attenuation of the spherically averaged power spectrum on average at relevant scales of
k
≈ 0.2–0.3 Mpc
−1
compared to ∼25% for the interferometric Millimetre-wave Intensity Mapping Experiment targeting shot noise from CO lines at
z
∼ 1–5 at scales of
k
≳ 1 Mpc
−1
. We also consider the nature and amplitude of errors introduced by simplified treatments of line broadening and find that while an approximation using a single effective velocity scale is sufficient for spherically averaged power spectra, a more careful treatment is necessary when considering other statistics such as higher multipoles of the anisotropic power spectrum or the voxel intensity distribution.
Abstract
We present the current state of models for the
z
∼ 3 carbon monoxide (CO) line intensity signal targeted by the CO Mapping Array Project (COMAP) Pathfinder in the context of its early ...science results. Our fiducial model, relating dark matter halo properties to CO luminosities, informs parameter priors with empirical models of the galaxy–halo connection and previous CO (1–0) observations. The Pathfinder early science data spanning wavenumbers
k
= 0.051–0.62 Mpc
−1
represent the first direct 3D constraint on the clustering component of the CO (1–0) power spectrum. Our 95% upper limit on the redshift-space clustering amplitude
A
clust
≲ 70
μ
K
2
greatly improves on the indirect upper limit of 420
μ
K
2
reported from the CO Power Spectrum Survey (COPSS) measurement at
k
∼ 1 Mpc
−1
. The COMAP limit excludes a subset of models from previous literature and constrains interpretation of the COPSS results, demonstrating the complementary nature of COMAP and interferometric CO surveys. Using line bias expectations from our priors, we also constrain the squared mean line intensity–bias product,
Tb
2
≲ 50
μ
K
2
, and the cosmic molecular gas density,
ρ
H2
< 2.5 × 10
8
M
⊙
Mpc
−3
(95% upper limits). Based on early instrument performance and our current CO signal estimates, we forecast that the 5 yr Pathfinder campaign will detect the CO power spectrum with overall signal-to-noise ratio of 9–17. Between then and now, we also expect to detect the CO–galaxy cross-spectrum using overlapping galaxy survey data, enabling enhanced inferences of cosmic star formation and galaxy evolution history.
Line-intensity mapping is an emerging field of observational work, with strong potential to fit into a larger effort to probe large-scale structure and small-scale astrophysical phenomena using ...multiple complementary tracers. Taking full advantage of such complementarity means, in part, undertaking line-intensity surveys with galaxy surveys in mind. We consider the potential for detection of a cross-correlation signal between COMAP and blind surveys based on photometric redshifts (as in COSMOS) or based on spectroscopic data (as with the HETDEX survey of Ly emitters). We find that obtaining accuracy in redshifts and 10−4 sources per Mpc3 with spectroscopic redshift determination should enable a CO-galaxy cross spectrum detection significance at least twice that of the CO auto spectrum. Either a future targeted spectroscopic survey or a blind survey like HETDEX may be able to meet both of these requirements.
ABSTRACT
We present the deconvolved distribution estimator (DDE), an extension of the voxel intensity distribution (VID), in the context of future observations proposed as part of the CO Mapping ...Array Project (COMAP). The DDE exploits the fact that the observed VID is a convolution of correlated signal intensity distributions and uncorrelated noise or interloper intensity distributions. By deconvolving the individual VID of two observables away from their joint VID in a Fourier-space operation, the DDE suppresses sensitivity to interloper emission while maintaining sensitivity to correlated components. The DDE thus improves upon the VID by reducing the relative influence of uncorrelated noise and interloper biases, which is useful in the context of COMAP observations that observe different rotational transitions of CO from the same comoving volume in different observing frequency bands. Fisher forecasts suggest that the theoretical sensitivity in the DDE allows significant improvements in constraining power compared to either the cross power spectrum or the individual VID data, and matches the constraining power of the combination of all other one- and two-point summary statistics. Future work should further investigate the covariance and model-dependent behaviour of this novel one-point cross-correlation statistic.
Abstract
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 (
z
∼ 5–8) in addition to providing a significant boost to the
z
∼ 3 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/Ns) ≳ 20 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
z
∼ 2–8, 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.
Abstract
Intensity-mapping observations measure galaxy clustering fluctuations from spectral–spatial maps, requiring stable noise properties on large angular scales. We have developed specialized ...readouts and analysis methods for achieving large-scale noise stability with Teledyne 2048 × 2048 H2RG infrared detector arrays. We designed and fabricated a room-temperature low-noise ASIC Video8 amplifier to sample each of the 32 detector outputs continuously in sample-up-the-ramp mode with interleaved measurements of a stable reference voltage that remove current offsets and 1/
f
noise from the amplifier. The amplifier addresses rows in an order different from their physical arrangement on the array, modulating temporal 1/
f
noise in the H2RG to high spatial frequencies. Finally, we remove constant signal offsets in each of the 32 channels using reference pixels. These methods will be employed in the upcoming SPHEREx orbital mission that will carry out intensity-mapping observations in near-infrared spectral maps in deep fields located near the ecliptic poles. We also developed a noise model for the H2RG and Video8 to optimize the choice of parameters. Our analysis indicates that these methods hold residual 1/
f
noise near the level of SPHEREx photon noise on angular scales smaller than ∼30′.
The submillimeter opacity of dust in the diffuse interstellar medium (ISM) in the Galactic plane has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy ...for column density. We used multi-wavelength continuum data: three Balloon-borne Large Aperture Submillimeter Telescope bands at 250,350, and 500 mu m and one IRAS band at 100 mu m. The proxy is the near-infrared color excess, E(J - K sub(s)), obtained from the Two Micron All Sky Survey. Based on observations of stars, we show how well this color excess is correlated with the total hydrogen column density for regions of moderate extinction. There is a range in total power per H nucleon absorbed (and re-radiated) by the dust, reflecting changes in the strength of the interstellar radiation field and/or the dust absorption opacity. These changes in emission opacity and power affect the equilibrium T, which is typically 15 K, colder than at high latitudes.
![Forecasting [C ii] Line-int...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0004-637X_1538-4357/small "Forecasting [C ii] Line-intensity Mapping Measurements between the End of Reionization and the Epoch of Galaxy Assembly")
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