Search Publications
The effects of the initial mass function on Galactic chemical enrichment
Lapi, A.; Bressan, A.; Grisoni, V. +7 more
Context. We have been seeing mounting evidence that the stellar initial mass function (IMF) might extend far beyond the canonical Mi ∼ 100 M⊙ limit, but the impact of such a hypothesis on the chemical enrichment of galaxies is yet to be clarified.
Aims: We aim to address this question by analysing the observed abundances…
Metallicities from high-resolution spectra of 49 RR Lyrae variables
Dall'Ora, Massimo; Bono, Giuseppe; Fiorentino, Giuliana +12 more
Accurate metallicities of RR Lyrae are extremely important in constraining period-luminosity-metallicity (PLZ) relationships, particularly in the near-infrared. We analyse 69 high-resolution spectra of Galactic RR Lyrae stars from the Southern African Large Telescope. We measure metallicities of 58 of these RR Lyrae stars with typical uncertaintie…
Primordial Black Holes Formation and Secondary Gravitational Waves in Nonminimal Derivative Coupling Inflation
Karami, Kayoomars; Teimoori, Zeinab; Rezazadeh, Kazem
We study the possibility of the primordial black holes (PBHs) formation with the aim of finding a considerable fraction of dark matter (DM), using the gravitationally enhanced friction mechanism which arises from a nonminimal derivative coupling between the scalar field and the gravity. Assuming the nonminimal coupling parameter as a special funct…
Far-UV and Optical Emissions from Three Very Large Supernova Remnants Located at Unusually High Galactic Latitudes
Raymond, John C.; Milisavljevic, Dan; Fesen, Robert A. +9 more
Galactic supernova remnants (SNRs) with angular dimensions greater than a few degrees are relatively rare, as are remnants located more than 10° off the Galactic plane. Here we report a UV and optical investigation of two previously suspected SNRs more than 10° in both angular diameter and Galactic latitude. One is a proposed remnant discovered in…
Simulating the infrared sky with a SPRITZ
Pozzi, F.; Rodighiero, G.; Feltre, A. +6 more
Aims: Current hydrodynamical and semi-empirical simulations of galaxy formation and evolution have difficulties in reproducing the number densities of infrared-detected galaxies. Therefore, a phenomenological simulation tool that is new and versatile is necessary to reproduce current and predict future observations at infrared (IR) wavelength…
Characterization of 92 southern TESS candidate planet hosts and a new photometric [Fe/H] relation for cool dwarfs
Nordlander, Thomas; Casagrande, Luca; Žerjal, Maruša +7 more
We present the results of a medium-resolution optical spectroscopic survey of 92 cool ($3000 \,\mathrm{ K}\lesssim T_{\rm eff} \lesssim 4500\,$K) southern TESS candidate planet hosts, and describe our spectral fitting methodology used to recover stellar parameters. We quantify model deficiencies at predicting optical fluxes, and while our techniqu…
Ubiquitous [O II] Emission in Quiescent Galaxies at z ≈ 0.85 from the LEGA-C Survey
Bell, Eric F.; Maseda, Michael V.; D'Eugenio, Francesco +12 more
Using deep rest-frame optical spectroscopy from the Large Early Galaxy Astrophysical Census (LEGA-C) survey, conducted using VIMOS on the ESO Very Large Telescope, we search for low-ionization [O II] λ λ 3726,3729 emission in the spectra of a mass-complete sample of z ≈ 0.85 galaxies. We find that 59% of UVJ-quiescent (i.e., non-star-forming) gala…
Stellar Dynamical Models for 797 z 0.8 Galaxies from LEGA-C
Bell, Eric F.; Maseda, Michael V.; Franx, Marijn +12 more
We present spatially resolved stellar kinematics for 797 z = 0.6-1 galaxies selected from the LEGA-C survey and construct axisymmetric Jeans models to quantify their dynamical mass and degree of rotational support. The survey is K s -band selected, irrespective of color or morphological type, and allows for a first assessment of the st…
Extreme r-process Enhanced Stars at High Metallicity in Fornax
Hansen, C. J.; Reichert, M.; Arcones, A.
We present and discuss three extremely r-process enhanced stars located in the massive dwarf spheroidal galaxy Fornax. These stars are very unique with an extreme Eu enrichment (1.25 ≤ [Eu/Fe]≤1.45) at high metallicities (-1.3 ≤ [Fe/H]≤-0.8). They have the largest Eu abundances ever observed in a dwarf galaxy opening new opportunities to further u…
Constraining the shear acceleration model for the X-ray emission of large-scale extragalactic jets
Tavecchio, F.
The nature of the intense X-ray emission from powerful extragalactic jets at large (>1 kpc) scale is still debated. The scenario that invokes the inverse Compton scattering of the cosmic microwave background by electrons is challenged by the lack of gamma-ray emission in the GeV band. An alternative assumes synchrotron emission by a distinct po…