Constraints on primordial non-Gaussianity (PNG) will shed light on the origin of primordial fluctuations and the physics of the early universe. The intensity mapping technique is a promising probe of ...structure formation on large scales; at high redshifts, it can provide complementary information to other cosmological probes. We explore the potential of future wide-field C ii and CO intensity mapping surveys in constraining PNG of the local shape, which induces a distinct, scale-dependent correction to the line bias. We explore the parameter space of CO and C ii survey designs that can achieve the nominal target of , and further calculate what constraints such surveys can place on PNG of the equilateral, orthogonal, and quasi-single field shapes. We further test the dependence of these constraints on various model assumptions; namely the halo mass function, modeling of line bias, and correlation between mass and C ii/CO luminosity. We find that the ability of CO and C ii intensity mapping surveys to constrain relies heavily on the spectral (redshift) coverage, requiring at least a coverage of an octave in frequency, to produce significant results, with the optimized surveys generally covering between z ∼ 2-8. As this redshift window partially overlaps with 21 cm EoR experiments like the Hydrogen Epoch of Reionization Array (HERA), we additionally explore the prospects for a hypothetical set of surveys to place constraints on utilizing multi-tracer analysis between the lines of H i, CO, and C ii.
ABSTRACT We present a measurement of the abundance of carbon monoxide in the early universe, utilizing the final results from the CO Power Spectrum Survey (COPSS). Between 2013 and 2015, we performed ...observations with the Sunyaev-Zel'dovich Array to measure aggregate CO emission from galaxies with the intensity mapping technique. Data were collected on 19 fields, covering an area of 0.7 square degrees, over the frequency range . With these data, along with data analyzed in COPSS I, we are able to observe the CO(1-0) transition within the redshift range for spatial frequencies between , spanning a comoving volume of . We present estimates of contributions from continuum sources and ground illumination within our measurement. We constrain the amplitude of the CO power spectrum to , or , at 68% confidence, and at 98.9% confidence. These results are a factor of 10 improvement in sensitivity compared to those of COPSS I. With this measurement, we constrain on the CO(1-0) galaxy luminosity function at . Assuming that CO emission is proportional to halo mass and using theoretical estimates of the scatter in this relationship, we constrain the ratio of luminosity to halo mass to . Assuming a Milky Way-like linear relationship between CO luminosity and molecular gas mass, we estimate a mass fraction of molecular gas of for halos with masses of . Using theoretical estimates for the scaling of molecular gas mass fraction and halo mass, we estimate the cosmic molecular gas density to be .
We present a detection of molecular gas emission at z ∼ 1-5 using the technique of line intensity mapping. We make use of a pair of 3 mm interferometric data sets, the first from the Atacama Large ...Millimeter/submillimeter Array (ALMA) Spectroscopic Survey in the Hubble Ultra Deep Field, and the second from a series of Atacama Compact Array (ACA) observations conducted between 2016 and 2018, targeting the COSMOS field. At 100 GHz, we measure nonzero power at 97.8% and 99.9% confidence in the ACA and ALMA data sets, respectively. In the joint result, we reject the zero-power hypothesis at 99.99% confidence, finding . After accounting for sample variance effects, the estimated spectral shot power is . We derive a model for the various line species our measurement is expected to be sensitive to, and estimate the shot power to be , , and for CO(2-1) at z = 1.3, CO(3-2) at z = 2.5, and CO(4-3) at z = 3.6, respectively. Using line ratios appropriate for high-redshift galaxies, we find these results to be in good agreement with those from the CO Power Spectrum Survey. Adopting CO = 3.6 M (K km s−1 pc2)−1, we estimate a cosmic molecular gas density of ∼ 108 M Mpc−3 between z = 1-3.
Abstract
Recent deep millimeter-wave surveys have attempted to measure the carbon monoxide (CO) luminosity function and mean molecular gas density through blind detections of CO emission lines. While ...the cosmic star formation rate density is now constrained in fields of hundreds of square arcminutes or more, molecular gas studies have been limited to ≤50 arcmin
2
. These small fields result in significant biases that have not been accounted for in published results. To quantify these biases, we assign CO luminosities to halos in cosmological simulations to produce mock observations for a range of field sizes. We find that fields of ≲10 arcmin
2
alter the recovered shape of the luminosity function, causing underestimates of the number of bright objects. Our models suggest that current surveys are sensitive enough to detect sources responsible for approximately half of the cosmic molecular gas density at high redshift. However, uncertainties in the gas density measurement are large, and cosmic variance may double the uncertainty claimed in these surveys. As a result, the field size needed to detect redshift evolution in the molecular gas at high confidence may be more than one order of magnitude larger than what current surveys have achieved. Shot power intensity mapping measurements are particularly sensitive to Poisson variance and require yet larger areas to constrain the gas density or its evolution. We provide a simple prescription for approximating uncertainty in total CO emission as a function of survey area and redshift for both direct detection and intensity mapping surveys.
Abstract
Line intensity mapping (LIM) is an emerging technique with a unique potential to probe a wide range of scales and redshifts. Realizing the full potential of LIM, however, relies on accurate ...modeling of the signal. We introduce an extended halo model for the power spectrum of intensity fluctuations of CO rotational lines and CII fine transition line in real space, modeling nonlinearities in matter fluctuations and biasing relation between the line intensity fluctuations and the underlying dark matter distribution. We also compute the stochastic contributions beyond the Poisson approximation using the halo model framework. To establish the accuracy of the model, we create the first cosmological-scale simulations of CO and CII intensity maps, MithraLIMSims, at redshifts 0.5 ≤ z≤6, using halo catalogs from Hidden-Valley simulations, and painting halos according to mass-redshift-luminosity relations for each line. We show that at z=1 on scales k
max
≲ 0.8 Mpc
-1
1h, the model predictions of clustering power (with only two free parameters) are in agreement with the measured power spectrum at better than 5%. At higher redshift of z=4.5, this remarkable agreement extends to smaller scale of k
max
≲ 2 Mpc
-1
1h. Furthermore, we show that on large scales, the stochastic contributions to CO and CII power spectra are non-Poissonian, with amplitudes reproduced reasonably well by the halo model prescription. Lastly, we assess the performance of the theoretical model of the baryon acoustic oscillations (BAO) and show that hypothetical LIM surveys probing CO lines at z=1, that can be deployed within this decade, will be able to make a high significance measurement of the BAO. On a longer time scale, a space-based mission probing CII line can uniquely measure the BAO on a wide range of redshifts at an unprecedented precision.
Abstract Line intensity mapping (LIM) can provide a powerful means to constrain the theory of gravity and the nature of dark energy at low and high redshifts by mapping the large-scale structure over ...many redshift epochs. In this paper, we investigate the potential of the next generation ground-based millimeter-wavelength LIM surveys in constraining several models beyond ΛCDM, involving either a dynamic dark energy component or modifications of the theory of gravity. Limiting ourselves to two-point clustering statistics, we consider the measurements of auto-spectra of several CO rotational lines (from J = 2−1 to J = 6−5) and the C ii fine structure line in the redshift range of 0.25 < z < 12. We consider different models beyond ΛCDM, each one with different signatures and peculiarities. Among them, we focus on Jordan–Brans–Dicke and axion-driven early dark energy models as examples of well-studied scalar-tensor theories acting at late and early times, respectively. Additionally, we consider three phenomenological models based on an effective description of gravity at cosmological scales. We show that LIM surveys deployable within a decade (with ∼10 8 spectrometer hours) have the potential to improve upon the current bounds on all considered models significantly. The level of improvements range from a factor of a few to an order of magnitude.
Abstract
Line intensity mapping (LIM) is emerging as a powerful technique to map the cosmic large-scale structure and to probe cosmology over a wide range of redshifts and spatial scales. We perform ...Fisher forecasts to determine the optimal design of wide-field ground-based millimeter-wavelength LIM surveys for constraining properties of neutrinos and light relics. We consider measuring the auto-power spectra of several CO rotational lines (from
J
= 2–1 to
J
= 6–5) and the C
ii
fine-structure line in the redshift range of 0.25 <
z
< 12. We study the constraints with and without interloper lines as a source of noise in our analysis, and for several one-parameter and multiparameter extensions of ΛCDM. We show that LIM surveys deployable this decade, in combination with existing cosmic microwave background (CMB; primary) data, could achieve order-of-magnitude improvements over Planck constraints on
N
eff
and
M
ν
. Compared to next-generation CMB and galaxy surveys, a LIM experiment of this scale could achieve bounds that are a factor of ∼3 better than those forecasted for surveys such as EUCLID (galaxy clustering), and potentially exceed the constraining power of CMB-S4 by a factor of ∼1.5 and ∼3 for
N
eff
and
M
ν
, respectively. We show that the forecasted constraints are not substantially affected when enlarging the parameter space, and additionally demonstrate that such a survey could also be used to measure ΛCDM parameters and the dark energy equation of state exquisitely well.
Primordial non-Gaussianity (PNG) is an invaluable window into the physical processes that gave rise to cosmological structure. The presence of local shape PNG imprints a distinct scale-dependent ...correction to the bias of dark matter tracers on large scales, which can be effectively probed via the technique of intensity mapping. Considering an upcoming generation of experiments, we demonstrate that intensity mapping of CO and C ii emission can improve upon the current best constraints from the Planck satellite. We show that measurement of the CO intensity power spectrum by a hypothetical next stage of the ground-based COMAP experiment can achieve and that the proposed CMB satellite mission PIXIE can achieve via measurement of the C ii intensity power spectrum.
Abstract
The abundance of cold molecular gas plays a crucial role in models of galaxy evolution. While deep spectroscopic surveys of CO emission lines have been a primary tool for measuring this ...abundance, the difficulty of these observations has motivated alternative approaches to studying molecular gas content. One technique, line intensity mapping, seeks to constrain the average molecular gas properties of large samples of individually undetectable galaxies through the CO brightness power spectrum. Here we present constraints on the cross-power spectrum between CO intensity maps and optical galaxy catalogs. This cross-measurement allows us to check for systematic problems in CO intensity mapping data, and validate the data analysis used for the auto-power spectrum measurement of the CO Power Spectrum Survey. We place a 2
σ
upper limit on the band-averaged CO-galaxy cross-power of
P
×
< 540
μ
K h
−3
Mpc
3
. Our measurement favors a nonzero 〈
T
CO
〉 at around 90% confidence and gives an upper limit on the mean molecular gas density at
z
∼ 2.6 of 7.7 × 10
8
M
⊙
Mpc
−3
. We forecast the expected cross-power spectrum by applying a number of literature prescriptions for the CO luminosity–halo mass relation to a suite of mock light cones. Under the most optimistic forecasts, the cross-spectrum could be detected with only moderate extensions of the data used here, while more conservative models could be detected with a factor of 10 increase in sensitivity. Ongoing CO intensity mapping experiments will target fields allowing for extensive cross-correlation analysis and should reach the sensitivity required to detect the cross-spectrum signal.
Abstract
We present 1.3 mm (230 GHz) observations of the recent and nearby Type II supernova, SN 2023ixf, obtained with the Submillimeter Array (SMA) at 2.6–18.6 days after explosion. The ...observations were obtained as part the SMA Large Program, POETS (Pursuit of Extragalactic Transients with the SMA). We do not detect any emission at the location of SN 2023ixf, with the deepest limits of
L
ν
(230 GHz) ≲ 8.6 × 10
25
erg s
−1
Hz
−1
at 2.7 and 7.7 days, and
L
ν
(230 GHz) ≲ 3.4 × 10
25
erg s
−1
Hz
−1
at 18.6 days. These limits are about a factor of 2 times dimmer than the millimeter emission from SN 2011dh (IIb), about 1 order of magnitude dimmer compared to SN 1993J (IIb) and SN 2018ivc (IIL), and about 30 times dimmer than the most luminous nonrelativistic SNe in the millimeter band (Type IIb/Ib/Ic). Using these limits in the context of analytical models that include synchrotron self-absorption and free–free absorption, we place constraints on the proximate circumstellar medium around the progenitor star, to a scale of ∼2 × 10
15
cm, excluding the range
M
̇
∼
few
×
10
−
6
−
10
−
2
M
⊙
yr
−1
(for a wind velocity,
v
w
= 115 km s
−1
, and ejecta velocity,
v
ej
∼ (1 − 2) × 10
4
km s
−1
). These results are consistent with an inference of the mass-loss rate based on optical spectroscopy (∼2 × 10
−2
M
⊙
yr
−1
for
v
w
= 115 km s
−1
), but are in tension with the inference from hard X-rays (∼7 × 10
−4
M
⊙
yr
−1
for
v
w
= 115 km s
−1
). This tension may be alleviated by a nonhomogeneous and confined CSM, consistent with results from high-resolution optical spectroscopy.
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