Microlensing survey combining  Roman and Euclid Space Telescopes

2021 ◽  
Author(s):  
Jean-Philippe Beaulieu ◽  
Etienne Bachelet
Keyword(s):  
Phase Space ◽  
Direct Measurement ◽  
Short Duration ◽  
Preliminary Evidence ◽  
Proper Motions ◽  
Space Telescopes ◽  
Primary Mode ◽  
Kepler Mission ◽  
Joint Mission ◽  
Detection Capabilities

<p>As the Kepler mission has done for hot exoplanets, the ESA Euclid and NASA Roman missions have the potential to create a breakthrough in our understanding of the demographics of cool exoplanets, including planets on very wide orbits, unbound, or "free-floating", planets (FFPs). Current ground-based microlensing observations have provided preliminary evidence for a potentially significant population of Super-Earth FFPs. Roman will dedicate part of its core survey program to the detection of cool exoplanets via microlensing, while Euclid may undertake a microlensing program as an ancillary science goal. We argue that simultaneous observations of short-duration microlensing events by Roman and Euclid will enable not just the verification of FFPs, but also a direct measurement of their masses, distances and transverse motions, via the detection of microlens parallax between Euclid and Roman. We use simulations of the joint-mission detection capabilities to show that parallax detections will be possible down to Earth-mass FFPs. The mass and phase-space measurements from a joint survey could thus provide strong clues to the primary mode of FFP formation.</p> <p>We also demonstrate that an early brief Euclid survey (∼5 h) of the Roman fields shortly after the Euclid launch would be also very valuable. It would allow the measurement of at least 10% of the events’  relative proper motions and 35% of the lens magnitudes very early on the life of the Roman Survey. We further discuss additional valuable science that will be facilitated by a joint Roman-Euclid microlensing campaign.</p>

scholarly journals Mass and shape of the Milky Way’s dark matter halo with globular clusters from Gaia and Hubble

2019 ◽  
Vol 621 ◽  
pp. A56 ◽  
Author(s):  
Lorenzo Posti ◽  
Amina Helmi
Keyword(s):  
Dark Matter ◽  
Phase Space ◽  
Globular Cluster ◽  
Globular Clusters ◽  
Cluster System ◽  
Dark Matter Halo ◽  
Proper Motions ◽  
Axis Ratio ◽  
The Galaxy ◽  
Globular Cluster System

Aims. We estimate the mass of the inner (< 20 kpc) Milky Way and the axis ratio of its inner dark matter halo using globular clusters as tracers. At the same time, we constrain the distribution in phase-space of the globular cluster system around the Galaxy. Methods. We use the Gaia Data Release 2 catalogue of 75 globular clusters’ proper motions and recent measurements of the proper motions of another 20 distant clusters obtained with the Hubble Space Telescope. We describe the globular cluster system with a distribution function (DF) with two components: a flat, rotating disc-like one and a rounder, more extended halo-like one. While fixing the Milky Way’s disc and bulge, we let the mass and shape of the dark matter halo and we fit these two parameters, together with six others describing the DF, with a Bayesian method. Results. We find the mass of the Galaxy within 20 kpc to be M(<20 kpc) = 1.91−0.17+0.18×1011 M⊙, of which MDM(<20 kpc) = 1.37−0.17+0.18×1011 M⊙ is in dark matter, and the density axis ratio of the dark matter halo to be q = 1.30 ± 0.25. Assuming a concentration-mass relation, this implies a virial mass Mvir = 1.3±0.3×1012 M⊙. Our analysis rules out oblate (q <  0.8) and strongly prolate halos (q >  1.9) with 99% probability. Our preferred model reproduces well the observed phase-space distribution of globular clusters and has a disc component that closely resembles that of the Galactic thick disc. The halo component follows a power-law density profile ρ ∝ r−3.3, has a mean rotational velocity of Vrot ≃ −14km s−1 at 20 kpc, and has a mildly radially biased velocity distribution (β ≃ 0.2 ± 0.07, which varies significantly with radius only within the inner 15 kpc). We also find that our distinction between disc and halo clusters resembles, although not fully, the observed distinction in metal-rich ([Fe/H] > −0.8) and metal-poor ([Fe/H] ≤ −0.8) cluster populations.

scholarly journals EXPANDING EJECTA IN THE OXYGEN-RICH SUPERNOVA REMNANT G292.0+1.8: DIRECT MEASUREMENT THROUGH PROPER MOTIONS

2009 ◽  
Vol 692 (2) ◽  
pp. 1489-1499 ◽  
Author(s):  
P. Frank Winkler ◽  
Karl Twelker ◽  
Claudine N. Reith ◽  
Knox S. Long
Keyword(s):  
Direct Measurement ◽  
Supernova Remnant ◽  
Proper Motions

scholarly journals Direct measurement of ion phase-space orbits in an electrostatic field

1989 ◽  
Vol 63 (19) ◽  
pp. 2052-2055 ◽  
Author(s):  
A. Fasoli ◽  
T. N. Good ◽  
F. Anderegg ◽  
F. Skiff ◽  
P. J. Paris ◽  
...  
Keyword(s):  
Phase Space ◽  
Direct Measurement ◽  
Electrostatic Field

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Catalogue reduction techniques

1978 ◽  
Vol 48 ◽  
pp. 389-390 ◽  
Author(s):  
Chr. de Vegt
Keyword(s):  
Adjustment Process ◽  
Proper Motions ◽  
Measuring Process ◽  
Aerial Photogrammetry ◽  
Reduction Techniques ◽  
Observational Technique ◽  
The Common ◽  
Astrometric Data

AbstractReduction techniques as applied to astrometric data material tend to split up traditionally into at least two different classes according to the observational technique used, namely transit circle observations and photographic observations. Although it is not realized fully in practice at present, the application of a blockadjustment technique for all kind of catalogue reductions is suggested. The term blockadjustment shall denote in this context the common adjustment of the principal unknowns which are the positions, proper motions and certain reduction parameters modelling the systematic properties of the observational process. Especially for old epoch catalogue data we frequently meet the situation that no independent detailed information on the telescope properties and other instrumental parameters, describing for example the measuring process, is available from special calibration observations or measurements; therefore the adjustment process should be highly self-calibrating, that means: all necessary information has to be extracted from the catalogue data themselves. Successful applications of this concept have been made already in the field of aerial photogrammetry.

Building Emotional Intelligence for Student Success: A Pilot Study

2019 ◽  
Vol 4 (6) ◽  
pp. 1445-1461
Author(s):  
Amee P. Shah ◽  
Mary Lou Galantino
Keyword(s):  
Emotional Intelligence ◽  
Emotional Regulation ◽  
Communication Apprehension ◽  
Communication Competence ◽  
Emotional Awareness ◽  
Self Esteem ◽  
Preliminary Evidence ◽  
Empowerment Model ◽  
Dyad Interaction ◽  
Relational Management

Purpose Nationwide, upward trends exist in student issues with anxiety, stress, depression, and lowered classroom performance. As emotional awareness and emotional regulation skills are typically not addressed in professional discipline-specific courses, students experience challenges in their academic performance. This pilot research explored the effect of brief targeted classroom practices within an empowerment-based framework on domains of emotional intelligence. Method Twenty-two students in an undergraduate speech-language pathology class received a 13-week, biweekly, 15-min session of empowerment-based worksheet exercises to develop increased self-esteem, emotional awareness and regulation, and communication. Assessments of self-esteem, emotional intelligence, communication competence, and communication apprehension were conducted using validated scales, namely, the Rosenberg Self-Esteem Scale ( Rosenberg, 1965 ), the Quick Emotional Intelligence Self-Assessment ( Mohapel, 2015 ), the Self-Perceived Communication Competence Scale ( McCroskey & McCroskey, 2013 ), and the Personal Report of Communication Apprehension ( McCroskey, 1982 ), respectively. Midsemester and semester-end student reflections were collected. Results Paired t tests were significant in self-esteem and emotional quotient, including subdomains of emotional awareness, emotional management, social emotional awareness, and relational management. Significance was noted in communication competence in the subdomains of dyad interaction, stranger interaction, and acquaintance. Students' reflection showed significant improvement in empowerment and self-rated improvements in confidence, communication, connections with peers, and trust with instructor. Conclusion Preliminary evidence demonstrates positive outcomes with integration of intentional classroom exercises to build emotional intelligence (including emotional awareness and regulation), self-esteem, and communication. This empowerment model may assist faculty in developing effective pedagogical strategies to build students' self-resiliency.

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