English
Related papers

Related papers: Murriyang cryogenic phased array feed: spectral-li…

200 papers

Fluorescence microscopy and derived techniques are continuously looking for photodetectors able to guarantee increased sensitivity, high spatial and temporal resolution and ease of integration into modern microscopy architectures. Recent…

New observations of the quasar HE0515$-$4414 have been made using the HARPS spectrograph on the ESO 3.6m telescope, aided by the Laser Frequency Comb (LFC). We present three important advances for $\alpha$ measurements in quasar absorption…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-08 Dinko Milaković , Chung-Chi Lee , Robert F. Carswell , John K. Webb , Paolo Molaro , Luca Pasquini

We have obtained high resolution spectra (R = 25000) of an A star over varying airmass to determine the effectiveness of telluric removal in the limit of high signal to noise. The near infra-red line HeI at 2.058 microns, which is a…

Astrophysics · Physics 2015-06-24 M. A. Kenworthy , M. M. Hanson

Radio interferometers are phased arrays producing high-resolution images from the covariance matrix of measurements. Calibration of such instruments is necessary and is a critical task. This is how the estimation of instrumental errors is…

Instrumentation and Methods for Astrophysics · Physics 2023-09-26 Yassine Mhiri , Mohammed Nabil El Korso , Arnaud Breloy , Pascal Larzabal

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

Solar and Stellar Astrophysics · Physics 2015-06-17 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , B. Freytag

We have used the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope to search for intervening 21 cm neutral hydrogen (HI) absorption along the line of sight to 53 bright radio continuum sources. Our observations are…

CARMENES is a dual-channel high-resolution spectrograph at the 3.5 m Calar Alto telescope designed to detect low-mass planets around late-type dwarfs by measuring their radial velocities (RVs). High thermal stability in both the visible…

In this report we present a model for phased array feed (PAF) and compare the model predictions with measurements. A theory for loss-less PAF is presented first. To develop the theory we ask the question -- what is the best…

Instrumentation and Methods for Astrophysics · Physics 2019-02-06 D. Anish Roshi , J. Richard Fisher

In radio astronomy, radio frequency interference (RFI) becomes more and more serious for radio observational facilities. The RFI always influences the search and study of the interesting astronomical objects. Mitigating the RFI becomes an…

Instrumentation and Methods for Astrophysics · Physics 2021-12-03 Chuan-Peng Zhang , Jin-Long Xu , Jie Wang , Yingjie Jing , Ziming Liu , Ming Zhu , Peng Jiang

The GASS is a survey of Galactic atomic hydrogen (HI) emission in the southern sky observed with the Parkes 64-m Radio Telescope. With a sensitivity of 60 mK for a channel width of 1 km/s the GASS is the most sensitive and most accurate…

Instrumentation and Methods for Astrophysics · Physics 2011-02-25 Peter M. W. Kalberla

We present and compare several methods to mitigate time-correlated (1/f) noise within the HI intensity mapping component of the MeerKAT Large Area Synoptic Survey (MeerKLASS). By simulating scan strategies, the HI signal, foreground…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-10 Melis O. Irfan , Yichao Li , Mario G. Santos , Philip Bull , Junhua Gu , Steven Cunnington , Keith Grainge , Jingying Wang

We present the in-lab and on-sky performance for the upgraded 90 GHz focal plane of the Cosmology Large Angular Scale Surveyor (CLASS), which had four of its seven detector wafers updated during the austral winter of 2022. The update aimed…

In this paper we explore the application of cryogenic imaging spectrophotometers. Prototypes of this new class of detector, such as superconducting tunnel junctions (STJs) and transition edge sensors (TESs), currently deliver low resolution…

Astrophysics · Physics 2009-10-31 Ben A. Mazin , Robert J. Brunner

Amplification is usually necessary when measuring the frequency instability of microwave signals. In this work, we develop a flicker noise free frequency measurement system based on a common or shared amplifier. First, we show that…

Instrumentation and Detectors · Physics 2012-02-23 Daniel L. Creedon , Michael E. Tobar , Eugene N. Ivanov , John G. Hartnett

Recent studies of the performance of radio-frequency (RF) copper cavities operated at cryogenic temperatures have shown a dramatic increase in the maximum achievable surface electric field. We propose to exploit this development to enable a…

Solid-state high harmonic generation spectroscopy (sHHG) is a promising technique for studying electronic structure, symmetry, and dynamics in condensed matter systems. Here, we report on the implementation of an advanced sHHG spectrometer…

This article shows the first measurement of three 100 MHz signals exhibiting fluctuations from 2E-16 to parts in 1E-15 for integration time tau between 1 s and 1 day. Such stable signals are provided by three Cryogenic Sapphire Oscillators…

Instrumentation and Detectors · Physics 2018-08-30 Claudio E. Calosso , François Vernotte , Vincent Giordano , Christophe Fluhr Benoît Dubois , Enrico Rubiolar

The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the Epoch of Reionization (EOR). Drawing on lessons from the Murchison Widefield…

Aperture arrays have been studied extensively for application in the next generation of large radio telescopes for astronomy, requiring extremely low noise performance. Prototype array systems need to demonstrate the low noise potential of…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 E. E. M. Woestenburg , L. Bakker , M. V. Ivashina

We investigate the effect of radio-frequency interference (RFI) excision in estimating the cosmological \hi\ 21 cm power spectrum. Flagging of RFI-contaminated channels results in a non-uniform sampling of the instrumental bandpass…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-27 Arnab Chakraborty , Abhirup Datta , Aishrila Mazumder
‹ Prev 1 3 4 5 6 7 10 Next ›