scholarly journals Intensity mapping cross-correlations: connecting the largest scales to galaxy evolution

2016 ◽  
Vol 458 (3) ◽  
pp. 3399-3410 ◽  
Author(s):  
L. Wolz ◽  
C. Tonini ◽  
C. Blake ◽  
J. S. B. Wyithe
Keyword(s):  
Galaxy Evolution ◽  
Intensity Mapping ◽  
Cross Correlations

scholarly journals Intensity mapping cross-correlations II: HI halo models including shot noise

2018 ◽  
Vol 484 (1) ◽  
pp. 1007-1020 ◽  
Author(s):  
L Wolz ◽  
S G Murray ◽  
C Blake ◽  
J S Wyithe
Keyword(s):  
Shot Noise ◽  
Intensity Mapping ◽  
Cross Correlations

scholarly journals Impact of foregrounds on H i intensity mapping cross-correlations with optical surveys

2019 ◽  
Vol 488 (4) ◽  
pp. 5452-5472 ◽  
Author(s):  
Steven Cunnington ◽  
Laura Wolz ◽  
Alkistis Pourtsidou ◽  
David Bacon
Keyword(s):  
Neutral Hydrogen ◽  
Optical Data ◽  
Line Of Sight ◽  
Redshift Distribution ◽  
Intensity Mapping ◽  
Fast Independent Component Analysis ◽  
Cross Correlations ◽  
The Cross ◽  
The Impact ◽  
Optical Surveys

ABSTRACT The future of precision cosmology could benefit from cross-correlations between intensity maps of unresolved neutral hydrogen (H i) and more conventional optical galaxy surveys. A major challenge that needs to be overcome is removing the 21cm foreground emission that contaminates the cosmological H i signal. Using N-body simulations, we simulate H i intensity maps and optical catalogues that share the same underlying cosmology. Adding simulated foreground contamination and using state-of-the-art reconstruction techniques, we investigate the impacts that 21cm foregrounds and other systematics have on these cross-correlations. We find that the impact a Fast Independent Component Analysis 21cm foreground clean has on the cross-correlations with spectroscopic optical surveys with well-constrained redshifts is minimal. However, problems arise when photometric surveys are considered: We find that a redshift uncertainty σz ≥ 0.04 causes significant degradation in the cross-power spectrum signal. We diagnose the main root of these problems, which relates to arbitrary amplitude changes along the line of sight in the intensity maps caused by the foreground clean and suggest solutions that should be applicable to real data. These solutions involve a reconstruction of the line-of-sight temperature means using the available overlapping optical data along with an artificial extension to the H i data through redshift to address edge effects. We then put these solutions through a further test in a mock experiment that uses a clustering-based redshift estimation technique to constrain the photometric redshifts of the optical sample. We find that with our suggested reconstruction, cross-correlations can be utilized to make an accurate prediction of the optical redshift distribution.

scholarly journals Neutral hydrogen in the post-reionization universe

2017 ◽  
Vol 12 (S333) ◽  
pp. 216-221
Author(s):  
Hamsa Padmanabhan
Keyword(s):  
Galaxy Evolution ◽  
Large Scale ◽  
Neutral Hydrogen ◽  
Lyman Alpha ◽  
Intensity Mapping ◽  
Best Fitting ◽  
Hydrodynamical Simulations ◽  
Intermediate Redshift ◽  
Intermediate Redshifts ◽  
The Universe

AbstractThe evolution of neutral hydrogen (HI) across redshifts is a powerful probe of cosmology, large scale structure in the universe and the intergalactic medium. Using a data-driven halo model to describe the distribution of HI in the post-reionization universe (z ∼ 5 to 0), we obtain the best-fitting parameters from a rich sample of observational data: low redshift 21-cm emission line studies, intermediate redshift intensity mapping experiments, and higher redshift Damped Lyman Alpha (DLA) observations. Our model describes the abundance and clustering of neutral hydrogen across redshifts 0 - 5, and is useful for investigating different aspects of galaxy evolution and for comparison with hydrodynamical simulations. The framework can be applied for forecasting future observations with neutral hydrogen, and extended to the case of intensity mapping with molecular and other line transitions at intermediate redshifts.

scholarly journals Exploring the dusty star-formation in the early Universe using intensity mapping

2017 ◽  
Vol 12 (S333) ◽  
pp. 228-233 ◽  
Author(s):  
Guilaine Lagache
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Light Emission ◽  
High Redshift ◽  
Structure Transition ◽  
Intensity Mapping ◽  
Infrared Background ◽  
The One ◽  
High Redshift Universe ◽  
2D And 3D

AbstractIn the last decade, it has become clear that the dust-enshrouded star formation contributes significantly to early galaxy evolution. Detection of dust is therefore essential in determining the properties of galaxies in the high-redshift universe. This requires observations at the (sub-)millimeter wavelengths. Unfortunately, sensitivity and background confusion of single dish observations on the one hand, and mapping efficiency of interferometers on the other hand, pose unique challenges to observers. One promising route to overcome these difficulties is intensity mapping of fluctuations which exploits the confusion-limited regime and measures the collective light emission from all sources, including unresolved faint galaxies. We discuss in this contribution how 2D and 3D intensity mapping can measure the dusty star formation at high redshift, through the Cosmic Infrared Background (2D) and [CII] fine structure transition (3D) anisotropies.

scholarly journals DISSECTING THE HIGH-zINTERSTELLAR MEDIUM THROUGH INTENSITY MAPPING CROSS-CORRELATIONS

2016 ◽  
Vol 833 (2) ◽  
pp. 153 ◽  
Author(s):  
Paolo Serra ◽  
Olivier Doré ◽  
Guilaine Lagache
Keyword(s):  
Intensity Mapping ◽  
Cross Correlations

scholarly journals The PAU survey: Lyα intensity mapping forecast

2020 ◽  
Author(s):  
Pablo Renard ◽  
Enrique Gaztanaga ◽  
Rupert Croft ◽  
Laura Cabayol ◽  
Jorge Carretero ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Narrow Band ◽  
Broad Band ◽  
Observation Time ◽  
Total Probability ◽  
Correlated Noise ◽  
Hydrodynamic Simulation ◽  
Intensity Mapping ◽  
Negative Results ◽  
Cross Correlations

Abstract In this work, we explore the application of intensity mapping to detect extended Lyα emission from the IGM via cross-correlation of PAUS images with Lyα forest data from eBOSS and DESI. Seven narrow-band (FWHM=13nm) PAUS filters have been considered, ranging from 455 to 515 nm in steps of 10 nm, which allows the observation of Lyα emission in a range 2.7 < z < 3.3. The cross-correlation is simulated first in an area of 100 deg2 (PAUS projected coverage), and second in two hypothetical scenarios: a deeper PAUS (complete up to iAB < 24 instead of iAB < 23, observation time x6), and an extended PAUS coverage of 225 deg2 (observation time x2.25). A hydrodynamic simulation of size 400 Mpc/h is used to simulate both extended Lyα emission and absorption, while the foregrounds in PAUS images have been simulated using a lightcone mock catalogue. Using an optimistic estimation of uncorrelated PAUS noise, the total probability of a non-spurious detection is estimated to be 1.8% and 4.5% for PAUS-eBOSS and PAUS-DESI , from a run of 1000 simulated cross-correlations with different realisations of instrumental noise and quasar positions. The hypothetical PAUS scenarios increase this probability to 15.3% (deeper PAUS) and 9.0% (extended PAUS). With realistic correlated noise directly measured from PAUS images, these probabilities become negligible. Despite these negative results, some evidences suggest that this methodology may be more suitable to broad-band surveys.

Central kiloparsec of NGC 1326 observed with SINFONI

2020 ◽  
Vol 638 ◽  
pp. A53
Author(s):  
Nastaran Fazeli ◽  
Gerold Busch ◽  
Andreas Eckart ◽  
Françoise Combes ◽  
Persis Misquitta ◽  
...  
Keyword(s):  
Black Hole ◽  
Galaxy Evolution ◽  
Near Infrared ◽  
Velocity Fields ◽  
Molecular Gas ◽  
Nearby Galaxy ◽  
Stellar Content ◽  
Stellar Rotation ◽  
Supermassive Black Hole ◽  
Integral Field Spectrograph

Gas inflow processes in the vicinity of galactic nuclei play a crucial role in galaxy evolution and supermassive black hole growth. Exploring the central kiloparsec of galaxies is essential to shed more light on this subject. We present near-infrared H- and K-band results of the nuclear region of the nearby galaxy NGC 1326, observed with the integral-field spectrograph SINFONI mounted on the Very Large Telescope. The field of view covers 9″ × 9″ (650 × 650 pc2). Our work is concentrated on excitation conditions, morphology, and stellar content. The nucleus of NGC 1326 was classified as a LINER, however in our data we observed an absence of ionised gas emission in the central r ∼ 3″. We studied the morphology by analysing the distribution of ionised and molecular gas, and thereby detected an elliptically shaped, circum-nuclear star-forming ring at a mean radius of 300 pc. We estimate the starburst regions in the ring to be young with dominating ages of < 10 Myr. The molecular gas distribution also reveals an elongated east to west central structure about 3″ in radius, where gas is excited by slow or mild shock mechanisms. We calculate the ionised gas mass of 8 × 105 M⊙ completely concentrated in the nuclear ring and the warm molecular gas mass of 187 M⊙, from which half is concentrated in the ring and the other half in the elongated central structure. The stellar velocity fields show pure rotation in the plane of the galaxy. The gas velocity fields show similar rotation in the ring, but in the central elongated H2 structure they show much higher amplitudes and indications of further deviation from the stellar rotation in the central 1″ aperture. We suggest that the central 6″ elongated H2 structure might be a fast-rotating central disc. The CO(3–2) emission observations with the Atacama Large Millimeter/submillimeter Array reveal a central 1″ torus. In the central 1″ of the H2 velocity field and residual maps, we find indications for a further decoupled structure closer to a nuclear disc, which could be identified with the torus surrounding the supermassive black hole.

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