Search Publications
Diffuse Galactic emission spectrum between 0.5 and 8.0 MeV
Calore, Francesca; Siegert, Thomas; Serpico, Pasquale D. +2 more
The last measurement of the diffuse emission spectrum of the Milky Way in the megaelectronvolt (MeV) photon energy range was performed by CGRO/COMPTEL more than 20 yr ago. We report a new analysis with the spectrometer SPI aboard INTEGRAL in the band 0.5-8.0 MeV, finally superseding the signal-to-noise ratio (S/N) of the historic observations. Thi…
Discovery of a thin lithium plateau among metal-poor red giant branch stars
Salaris, M.; Bonifacio, P.; Spite, M. +5 more
The surface lithium abundance, A(Li), of warm metal-poor dwarf stars exhibits a narrow plateau down to [Fe/H] ~ −2.8 dex, while at lower metallicities the average value drops by 0.3 dex with a significant star-by-star scatter (called `lithium meltdown'). This behaviour is in conflict with predictions of standard stellar evolution models calculated…
Observations of the initial formation and evolution of spiral galaxies at 1 < z < 3 in the CANDELS fields
Conselice, Christopher J.; Simmons, Brooke; Masters, Karen +4 more
Many aspects concerning the formation of spiral and disc galaxies remain unresolved, despite their discovery and detailed study over the past 150 yr. As such, we present the results of an observational search for proto-spiral galaxies and their earliest formation, including the discovery of a significant population of spiral-like and clumpy galaxi…
TOI-2257 b: A highly eccentric long-period sub-Neptune transiting a nearby M dwarf
Bouchy, F.; Queloz, D.; Stern, D. +64 more
Context. Thanks to the relative ease of finding and characterizing small planets around M-dwarf stars, these objects have become cornerstones in the field of exoplanet studies. The current paucity of planets in long-period orbits around M dwarfs makes such objects particularly compelling as they provide clues about the formation and evolution of t…
The Metallicity and Distance of NGC 2403 from Blue Supergiants
Bresolin, Fabio; Kudritzki, Rolf-Peter; Urbaneja, Miguel A.
We present the first quantitative spectral analysis of blue supergiant stars in the nearby galaxy NGC 2403. Out of a sample of 47 targets observed with the LRIS spectrograph at the Keck I telescope we have extracted 16 B- and A-type supergiants for which we have data of sufficient quality to carry out a comparison with model spectra of evolved mas…
The Eel Pulsar Wind Nebula: A PeVatron-candidate Origin for HAWC J1826-128 and HESS J1826-130
Woo, Jooyun; An, Hongjun; Gelfand, Joseph D. +8 more
HAWC J1826-128 is one of the brightest Galactic TeV γ-ray sources detected by the High Altitude Water Cherenkov (HAWC) observatory, with photon energies extending up to nearly ~100 TeV. This HAWC source spatially coincides with the H.E.S.S. TeV source HESS J1826-130 and the "Eel" pulsar wind nebula (PWN), which is associated with the GeV pulsar PS…
Compton-thick AGN in the NuSTAR Era. VIII. A joint NuSTAR-XMM-Newton Monitoring of the Changing-look Compton-thick AGN NGC 1358
Pozzi, F.; Buchner, J.; Feltre, A. +18 more
We present the multi-epoch monitoring with NuSTAR and XMM-Newton of NGC 1358, a nearby Seyfert 2 galaxy whose properties made it a promising candidate X-ray changing-look active galactic nucleus (AGN), i.e., a source whose column density could transition from its 2017 Compton-thick (having LOS hydrogen column density N H,LOS > 10
Extragalactic Magnetism with SOFIA (SALSA Legacy Program). III. First Data Release and On-the-fly Polarization Mapping Characterization
Beckman, John E.; Reach, William T.; Dale, Daniel A. +17 more
We describe the data processing of the Survey on extragALactic magnetiSm with SOFIA (SALSA Legacy Program). This first data release presents 33% (51.34 hr out of 155.7 hr, including overheads) of the total awarded time from 2020 January to 2021 December. Our observations were performed using the newly implemented on-the-fly mapping (OTFMAP) techni…
Dust distributions in the magellanic clouds
Chen, B. -Q.; Yang, M.; Gao, J. +3 more
We present high-resolution maps of the dust reddening in the Magellanic Clouds (MCs). The maps cover the Large and Small Magellanic Cloud (LMC and SMC) area and have a spatial angular resolution between ~26 arcsec and 55 arcmin. Based on the data from the optical and near-infrared (IR) photometric surveys, including the Gaia Survey, the SkyMapper …
Additional Evidence for a Pulsar Wind Nebula in the Heart of SN 1987A from Multiepoch X-Ray Data and MHD Modeling
Greco, Emanuele; Vink, Jacco; Miceli, Marco +9 more
Since the day of its explosion, supernova (SN) 1987A has been closely monitored to study its evolution and to detect its central compact relic. In fact, the formation of a neutron star is strongly supported by the detection of neutrinos from the SN. However, besides the detection in the Atacama Large Millimeter/submillimeter Array (ALMA) data of a…