Search Publications
In the Trenches of the Solar-stellar Connection. IV. Solar Full-disk Scans of C II, Si IV, and Mg II by the Interface Region Imaging Spectrograph
Testa, Paola; De Pontieu, Bart; Ayres, Thomas
About once a month, the Interface Region Imaging Spectrograph conducts day-long raster scans of the full Sun in three ultraviolet spectral channels. These full-disk mosaics are valuable in the solar context, but provide a unique connection to the distant, unresolved stars. Here, 10 deep-exposure scans (4-8 s per slit step), collected during the pe…
Low-energy electromagnetic processes affecting free-falling test-mass charging for LISA and future space interferometers
Grimani, Catia; Villani, Mattia; Fabi, Michele +1 more
Galactic cosmic rays and solar energetic particles charge gold-platinum, free-falling test masses (TMs) on board interferometers for the detection of gravitational waves in space. The charging process induces spurious forces on the test masses that affect the sensitivity of these instruments mainly below 10-3 Hz. Geant4 and FLUKA Monte …
In the Trenches of the Solar-Stellar Connection. III. The HST/COS Ecliptic-poles Stellar Survey (EclipSS)
Ayres, Thomas R.
The Ecliptic-poles Stellar Survey (EclipSS) collected far-ultraviolet (FUV: 1160-1420 Å) spectra of 49 nearby (d ≲ 100 pc) F3-K3 main-sequence stars, located at high ecliptic latitudes (north and south), using the Cosmic Origins Spectrograph of the Hubble Space Telescope. The ecliptic poles receive higher exposures from scanning missions like the …
A Hard Look at Relativistic Reverberation in MCG-5-23-16 and SWIFT J2127.4+5654: Testing the Lamppost Model
Miller, J. M.; Zoghbi, A.; Cackett, E.
X-ray reverberation mapping has emerged as a new tool to probe accretion in active galactic nuclei (AGN), providing a potentially powerful probe of accretion at the black hole scale. The lags, along with relativistic spectral signatures are often interpreted in light of the lamppost model. Focusing specifically on testing the prediction of the rel…
The Merger Dynamics of the Galaxy Cluster A1775: New Insights from Chandra and XMM-Newton for a Cluster Simultaneously Hosting a Wide-angle Tail and a Narrow-angle Tail Radio Source
Hu, Dan; Xu, Haiguang; Zhu, Zhenghao +13 more
We present a new study of the merger dynamics of A1775 by analyzing the high-quality Chandra and XMM-Newton archival data. We confirm/identify an arc-shaped edge (i.e., the head) at ∼48 kpc west of the X-ray peak, a split cold gas tail that extends eastward to ∼163 kpc, and a plume of spiral-like X-ray excess (within about 81-324 kpc northeast of …
The origin of the soft X-ray excess in the narrow-line Seyfert 1 galaxy SBS 1353 + 564
Gu, Qiusheng; Guo, Xiaotong; Ding, Nan +2 more
We present for the first time the timing and spectral analyses for a narrow-line Seyfert 1 galaxy, SBS 1353 + 564, using XMM-Newton and Swift multiband observations from 2007 to 2019. Our main results are as follows: (1) The temporal variability of SBS 1353+564 is random, while the hardness ratio is relatively constant over a time span of 13 yr; (…
Multiple Populations in Low-mass Globular Clusters: Palomar 13
Carballo-Bello, Julio A.; Li, Chengyuan; Cabrera-Lavers, Antonio +7 more
Since the discovery of chemically peculiar stars in globular clusters in the last century, the study of multiple populations has become increasingly important, given that chemical inhomogeneity is found in almost all globular clusters. Despite various proposed theories attempting to explain this phenomenon, fitting all the observational evidence i…
Magnetic chemically peculiar stars investigated by the Solar Mass Ejection Imager
Paunzen, E.; Prišegen, M.; Bernhard, K. +2 more
Since the discovery of the spectral peculiarities of their prototype α2 Canum Venaticorum in 1897, the so-called ACV variables, which are comprised of several groups of chemically peculiar stars of the upper main sequence, have been the target of numerous photometric and spectroscopic studies. Especially for the brighter ACV variables, …
Towards a robust estimation of orientation parameters between ICRF and Gaia celestial reference frames
Malkin, Zinovy
An analysis of the source position differences between very long baseline interferometry-based ICRF and Gaia-celestial reference frame catalogues is a key step in assessing their systematic errors and determining their mutual orientation. One of the main factors that limits the accuracy of determination of the orientation parameters between two fr…
Dense gas in local galaxies revealed by multiple tracers
Li, Juan; Gong, Yan; Li, Shanghuo +6 more
We present 3 mm and 2 mm band simultaneously spectroscopic observations of HCN 1-0, HCO+ 1-0, HNC 1-0, and CS 3-2 with the IRAM 30 m telescope, towards a sample of 70 sources as nearby galaxies with infrared luminosities ranging from several 10$^{5}\, \mathrm{L}_{\odot }$ to more than 10$^{12}\, \mathrm{L}_{\odot }$. After combining HCN…