相关论文: Spatial and Temporal Variations of the Chandra ACI…

Substellar companions such as exoplanets and brown dwarfs exhibit changes in brightness arising from top-of-atmosphere inhomogeneities, providing insights into their atmospheric structure and dynamics. This variability can be measured in…

Up to 2020, the Chandra ACIS gain has been calibrated using the External Calibration Source (ECS). The ECS consists of an Fe-55 radioactive source and is placed in the ACIS housing such that all chips are fully illuminated. Since the…

Soon after launch, the Advanced CCD Imaging Spectrometer (ACIS), one of the focal plane instruments on the Chandra X-ray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation…

We have developed and characterized an imaging instrument to measure the spatial properties of the diffuse near-infrared extragalactic background light in a search for fluctuations from z > 6 galaxies during the epoch of reionization. The…

We study the properties of the diffuse X-ray background by using the results of a cosmological hydrodynamical simulation of the concordance LambdaCDM model. The simulation follows gravitational and gas dynamics and includes a treatment of…

Precise, unbiased measurements of extragalactic background anisotropies require careful treatment of systematic effects in fluctuation-based, broad-band intensity mapping measurements. In this paper we detail improvements in methodology for…

Detecting oscillations in solar and stellar time series is complicated by non-stationary red noise and evolving background emission. Methods based on detrending and AR(1)-based wavelet analysis can introduce spurious periodicities and do…

We present the results of a 17 ks Chandra ACIS-S observation of the nearby dwarf spiral galaxy NGC 4395. Chandra affords the first high-quality, broadband X-ray detection of the active nucleus of this object that is uncontaminated by nearby…

The front-illuminated (FI) CCDs in the Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory (Chandra) were damaged in the extreme environment of the Earth's radiation belts, causing charge traps that result in enhanced…

We present an improved background model for the Large Area X-ray Proportional Counter (LAXPC) detectors on-board AstroSat. Because of the large collecting area and high pressure, the LAXPC instrument has a large background count rate, which…

We studied the X-ray variability of sources detected in the Chandra Deep Field South (Giacconi et al. 2002), nearly all of which are low to moderate z AGN (Tozzi et al. 2001). We find that 45% of the sources with >100 counts exhibit…

This paper provides a detailed description of the data reduction and analysis procedures that have been employed in our previous studies of spatial fluctuation of the cosmic infrared background (CIB) using deep Spitzer IRAC observations.…

The Advanced CCD Imaging Spectrometer is an instrument on the Chandra X-ray Observatory. CCDs are vulnerable to radiation damage, particularly by soft protons in the radiation belts and solar storms. The Chandra team has implemented…

Understanding the variability of Sagittarius A* (Sgr A*) requires coordinated, multi-wavelength observations that span the electromagnetic spectrum. In this work, we focus on data from four key observatories: Chandra in the X-ray (2-8 keV),…

We present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral shape and independent of temporal and…

The NASA PACE mission provides unprecedented hyperspectral observations of ocean color, aerosols, and clouds, offering new insights into how these components interact and influence Earth's climate and air quality. Its Ocean Color Instrument…

There exists an inordinate amount of spectral data in both public and private astronomical archives which remain severely under-utilised. The lack of reliable open-source tools for analysing large volumes of spectra contributes to this…

We are undertaking a large-scale, Micro-Arcsecond Scintillation-Induced Variability (MASIV) survey of the northern sky, Dec > 0 deg, at 4.9 GHz with the VLA. Our objective is to construct a sample of 100 to 150 scintillating extragalactic…

Ground-based observations at thermal infrared wavelengths suffer from large background radiation due to the sky, telescope and warm surfaces in the instrument. This significantly limits the sensitivity of ground-based observations at…

Microseismic source imaging plays a significant role in passive seismic monitoring. However, such a process is prone to failure due to aliasing when dealing with sparsely measured data. Thus, we propose a direct microseismic imaging…