154 research outputs found
(Un)conscious Bias in the Astronomical Profession: Universal Recommendations to improve Fairness, Inclusiveness, and Representation
(Un)conscious bias affects every aspect of the astronomical profession, from
scientific activities (e.g., invitations to join collaborations, proposal
selections, grant allocations, publication review processes, and invitations to
attend and speak at conferences) to activities more strictly related to career
advancement (e.g., reference letters, fellowships, hiring, promotion, and
tenure). For many, (un)conscious bias is still the main hurdle to achieving
excellence, as the most diverse talents encounter bigger challenges and
difficulties to reach the same milestones than their more privileged
colleagues. Over the past few years, the Space Telescope Science Institute
(STScI) has constructed tools to raise awareness of (un)conscious bias and has
designed guidelines and goals to increase diversity representation and outcome
in its scientific activities, including career-related matters and STScI
sponsored fellowships, conferences, workshops, and colloquia. STScI has also
addressed (un)conscious bias in the peer-review process by anonymizing
submission and evaluation of Hubble Space Telescope (and soon to be James Webb
Space Telescope) observing proposals. In this white paper we present a plan to
standardize these methods with the expectation that these universal
recommendations will truly increase diversity, inclusiveness and fairness in
Astronomy if applied consistently throughout all the scientific activities of
the Astronomical community.Comment: 7 pages, 3 figures, White Paper for Planetary Science and
Astrobiology Decadal Survey 2022. arXiv admin note: substantial text overlap
with arXiv:1907.0526
The Complex Star Formation History of NGC 1569
We present new results on the star formation history of the dwarf irregular
galaxy NGC 1569. The data were obtained with Hubble Space Telescope's
NICMOS/NIC2 in the F110W (J) and F160W (H) near-infrared (NIR) filters and
interpreted with the synthetic color-magnitude diagram method. The galaxy
experienced a complex star formation (SF) activity. The best fit to the data is
found by assuming three episodes of activity in the last 1-2 Gyr. The most
recent and strong episode constrained by these NIR data started ~37 Myr ago and
ended ~13 Myr ago, although we cannot exclude the possibility that up to three
SF episodes occurred in this time interval. The average star-formation rate
(SFR) of the episode is 3.2 Msun yr-1 kpc-2, in agreement with literature data.
A previous episode produced stars between 150 Myr and 40 Myr ago, with a mean
SFR about 2/3 lower than the mean SFR of the youngest episode. An older SF
episode occurred about 1 Gyr ago. All these SFRs are 2-3 orders of magnitude
higher than those derived for late-type dwarfs of the Local Group. In all cases
an initial mass function similar to Salpeter's allows for a good reproduction
of the data, but we cannot exclude flatter mass functions. These results have
been obtained adopting a distance of 2.2 Mpc and a reddening E(B-V)=0.56. A
larger distance would require younger episodes and higher SFRs. We have
explored some possible scenarios using the astrated mass in the best fit model,
in order to constrain the past star formation history. We cannot rule out a low
rate in the past SF but we can safely conclude that the last 1-2 Gyr have been
peculiar.Comment: Accepted by AJ, 2005, vol 129, 14 pages, 9 figure
Clinical features of COVID-19 and SARS epidemics. A literature review
SARS-CoV-2, responsible for the current pandemic, is a novel strain of the Coronaviridae family, which has infected humans as a result of the leap to a new species. It causes an atypical pneumonia similar to that caused by SARS-CoV in 2003. SARS-CoV-2 has currently infected more than 9.200.000 people and caused almost 480.000 deaths worldwide. Although SARS-CoV-2 and SARS-CoV have similar phylogenetic and pathogenetic characteristics, they show important differences in clinical manifestations.
We have reviewed the recent literature comparing the characteristics of the two epidemics and highlight their peculiar aspects. An analysis of all signs and symptoms of 3,365 SARS patients and 23,280 COVID-19 patients as well as of the comorbidities has been carried out. A total of 19 and 75 studies regarding patients with SARS and COVID-19, respectively, were included in the analysis. The analysis revealed an overlap of some symptoms between the two infections. Unlike SARS patients, COVID-19 patients have developed respiratory, neurological and gastrointestinal symptoms, and, in a limited number of subjects, symptoms involving organs such as skin and subcutaneous tissue, kidneys, cardiovascular system, liver and eyes.
This analysis was conducted in order to direct towards an early identification of the infection, a suitable diagnostic procedure and the adoption of appropriate containment measures
RESOLVING IONIZATION and METALLICITY on PARSEC SCALES ACROSS MRK 71 with HST-WFC3
Blue compact dwarf (BCD) galaxies in the nearby universe provide a means for studying feedback mechanisms and star formation processes in low-metallicity environments in great detail. Owing to their vicinity, these local analogs to primordial young galaxies are well suited for high-resolution studies that are unfeasible for high-redshift galaxies. Here we present Hubble Space Telescope Wide Field Camera 3 observations of one such BCD, Mrk 71, one of the most powerful local starbursts known, in the light of [O ii], He ii, Hβ, [O iii], Hα, and [S ii]. At D sime 3.44 Mpc, this extensive suite of emission-line images enables us to explore the chemical and physical conditions of Mrk 71 on ~2 pc scales. We use emission-line diagnostics to distinguish ionization mechanisms on a pixel-by-pixel basis and show that despite the previously reported hypersonic gas and superbubble blowout, the gas in Mrk 71 is photoionized, with no sign of shock-excited emission. He ii emission line images are used to identify up to six Wolf-Rayet stars, three of which lie on the edge of a blowout region. Using strong-line metallicity diagnostics, we present the first "metallicity image" of a galaxy, revealing chemical inhomogeneity on scales of <50 pc. We additionally demonstrate that while chemical structure can be lost at large scales, metallicity diagnostics can break down on spatial scales smaller than an H ii region. This study highlights not only the benefits of high-resolution spatially resolved observations in assessing the effects of feedback mechanisms but also the potential limitations when employing emission-line diagnostics; these results are particularly relevant as we enter the era of extremely large telescopes
Introduzione. Abitudine e letteratura
Starting from antiquity, the concept of habit has traversed the entire history of Western
philosophy and has represented one of the great themes of modern and contemporary
literature. The reflection on habit has raised questions concerning the relationship
between body and mind, the problem of time and the (re)construction of identity, the
conscious and the unconscious, and the role of memory.
This dossier addresses these questions from an aesthetic perspective, at the crossroads
between the history of philosophy and the history of literature
Hubble Tarantula Treasury Project. IV. The extinction law
We report on the study of interstellar extinction across the Tarantula nebula
(30 Doradus), in the Large Magellanic Cloud, using observations from the Hubble
Tarantula Treasury Project in the 0.3 - 1.6 micron range. The considerable and
patchy extinction inside the nebula causes about 3500 red clump stars to be
scattered along the reddening vector in the colour-magnitude diagrams, thereby
allowing an accurate determination of the reddening slope in all bands. The
measured slope of the reddening vector is remarkably steeper in all bands than
in the the Galactic diffuse interstellar medium. At optical wavelengths, the
larger ratio of total-to-selective extinction, namely Rv = 4.5 +/- 0.2, implies
the presence of a grey component in the extinction law, due to a larger
fraction of large grains. The extra large grains are most likely ices from
supernova ejecta and will significantly alter the extinction properties of the
region until they sublimate in 50 - 100 Myr. We discuss the implications of
this extinction law for the Tarantula nebula and in general for regions of
massive star formation in galaxies. Our results suggest that fluxes of strongly
star forming regions are likely to be underestimated by a factor of about 2 in
the optical.Comment: 15 pages, 10 figures, accepted for publication in MNRAS; Updated
references, corrected typos in Table
- …