DSpace Angular :: Browsing by Author "D'Ago, G."

Browsing by Author "D'Ago, G."

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An analysis of binary microlensing event OGLE-2015-BLG-0060
(2019) Tsapras, Y.; Cassan, A.; Ranc, C.; Bachelet, E.; Street, R.; Udalski, A.; Hundertmark, M.; Bozza, V.; Beaulieu, J. P.; Rabus, Markus; Marquette, J. B.; Euteneuer, E.; Bramich, D. M.; Dominik, M.; Jaimes, R. F.; Horne, K.; Mao, S.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; Mroz, P.; Szymanski, M. K.; Soszynski, I.; Skowron, J.; Pietrukowicz, Pawel; Kozlowski, S.; Poleski, R.; Ulaczyk, K.; Pawlak, M.; Jorgensen, U. G.; Skottfelt, J.; Popovas, A.; Ciceri, S.; Korhonen, H.; Kuffmeier, M.; Evans, D. F.; Peixinho, N.; Hinse, T. C.; Burgdorf, M. J.; Southworth, J.; Tronsgaard, R.; Kerins, E.; Andersen, M. I.; Rahvar, S.; Wang, Y.; Wertz, O.; Novati, S. C.; D'Ago, G.; Scarpetta, G.; Mancini, L.; Abe, F.; Asakura, Y.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Kawasaki, K.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Miyazaki, S.; Nagakane, M.; Ohnishi, K.; Rattenbury, N.; Saito, T.; Sharan, A.; Shibai, H.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yonehara, A.
Discovery of Two Einstein Crosses from Massive Post-blue Nugget Galaxies at z > 1 in KiDS*
(2020) Napolitano, N. R.; Li, R.; Spiniello, C.; Tortora, C.; Sergeyev, A.; D'Ago, G.; Guo, X.; Xie, L.; Radovich, M.; Roy, N.; Koopmans, L. V. E.; Kuijken, K.; Bilicki, M.; Erben, T.; Getman, F.; Heymans, C.; Hildebrandt, H.; Moya, C.; Shan, H. Y.; Vernardos, G.; Wright, A. H.
We report the discovery of two Einstein Crosses (ECs) in the footprint of the Kilo-Degree Survey (KiDS): KIDS J232940-340922 and KIDS J122456+005048. Using integral field spectroscopy from the Multi Unit Spectroscopic Explorer at the Very Large Telescope, we confirm their gravitational-lens nature. In both cases, the four spectra of the source clearly show a prominence of absorption features, hence revealing an evolved stellar population with little star formation. The lensing model of the two systems, assuming a singular isothermal ellipsoid (SIE) with external shear, shows that: (1) the two crosses, located at redshift z = 0.38 and 0.24, have Einstein radius R-E = 5.2 kpc and 5.4 kpc, respectively; (2) their projected dark matter fractions inside the half effective radius are 0.60 and 0.56 (Chabrier initial mass function); (3) the sources are ultra-compact galaxies, R-e similar to 0.9 kpc (at redshift, z(s) = 1.59) and R-e similar to 0.5 kpc (z(s) = 1.10), respectively. These results are unaffected by the underlying mass density assumption. Due to size, blue color, and absorption-dominated spectra, corroborated by low specific star formation rates derived from optical-near-infrared spectral energy distribution fitting, we argue that the two lensed sources in these ECs are blue nuggets migrating toward their quenching phase.
Exploring the crowded central region of ten Galactic globular clusters using EMCCDs Variable star searches and new discoveries
(2016) Jaimes, R.; Bramich, D.; Skottfelt, J.; Kains, N.; Jorgensen, U.; Horne, K.; Dominik, M.; Alsubai, K.; Bozza, V.; Rabus, Markus; Novati, S.; Ciceri, S.; D'Ago, G.; Galianni, P.; Gu, S.
Fornax3D project: Assembly history of massive early-type galaxies in the Fornax cluster from deep imaging and integral field spectroscopy
(2022) Spavone, M.; Iodice, E.; D'Ago, G.; van de Ven, G.; Morelli, L.; Corsini, E. M.; Sarzi, M.; Coccato, L.; Fahrion, K.; Falcon-Barroso, J.; Gadotti, D. A.; Lyubenova, M.; Martin-Navarro, I.; McDermid, R. M.; Pinna, F.; Pizzella, A.; Poci, A.; de Zeeuw, P. T.; Zhu, L.
This work is based on high-quality integral-field spectroscopic data obtained with the Multi Unit Spectroscopic Explorer (MUSE) on the Very Large Telescope (VLT). The 21 brightest (m(B) <= 15 mag) early-type galaxies (ETGs) inside the virial radius of the Fornax cluster are observed out to distances of similar to 2-3 R-e. Deep imaging from the VLT Survey Telescope (VST) is also available for the sample ETGs. We investigated the variation of the galaxy structural properties as a function of the total stellar mass and cluster environment. Moreover, we correlated the size scales of the luminous components derived from a multi-component decomposition of the VST surface-brightness radial profiles of the sample ETGs with the MUSE radial profiles of stellar kinematic and population properties. The results are compared with both theoretical predictions and previous observational studies and used to address the assembly history of the massive ETGs of the Fornax cluster. We find that galaxies in the core and north-south clump of the cluster, which have the highest accreted mass fraction, show milder metallicity gradients in their outskirts than the galaxies infalling into the cluster. We also find a segregation in both age and metallicity between the galaxies belonging to the core and north-south clump and the infalling galaxies. The new findings fit well within the general framework for the assembly history of the Fornax cluster.
High-precision photometry by telescope defocussing – VIII. WASP-22, WASP-41, WASP-42 and WASP-55
(2016) Southworth, J.; Tregloan, J.; Andersen, M.; Novati, S.; Ciceri, S.; Colque, J.; D'Ago, G.; Dominik, M.; Evans, D.; Rabus, Markus; Herrera, A.; Hinse, T.; Jorgensen, U.; Juncher, D.; Kuffmeier, M.; Gu, S.
INSPIRE: INvestigating Stellar Population In RElics - IV. The initial mass function slope in relics
(2023) Martin-Navarro, Ignacio; Spiniello, C.; Tortora, C.; Coccato, L.; D'Ago, G.; Ferre-Mateu, A.; Pulsoni, C.; Hartke, J.; Arnaboldi, M.; Hunt, L.; Napolitano, N. R.; Scognamiglio, D.; Spavone, M.
In the last decade, growing evidence has emerged supporting a non-universal stellar initial mass function (IMF) in massive galaxies, with a larger number of dwarf stars with respect to the Milky Way (bottom-heavy IMF). However, a consensus about the mechanisms that cause IMF variations is yet to be reached. Recently, it has been suggested that stars formed early-on in cosmic time, via a star formation burst, could be characterized by a bottom-heavy IMF. A promising way to confirm this is to use relics, ultra-compact massive galaxies, almost entirely composed by these 'pristine' stars. The INvestigating Stellar Population In RElics (INSPIRE) Project aims at assembling a large sample of confirmed relics, that can serve as laboratory to investigate on the conditions of star formation in the first 1-3 Gyr of the Universe. In this third INSPIRE paper, we build a high signal-to-noise spectrum from five relics, and one from five galaxies with similar sizes, masses, and kinematical properties, but characterized by a more extended star formation history (non-relics). Our detailed stellar population analysis suggests a systematically bottom-heavier IMF slope for relics than for non-relics, adding new observational evidence for the non-universality of the IMF at various redshifts and further supporting the above proposed physical scenario.
INSPIRE: INvestigating Stellar Population In RElics II. First data release (DR1)
(2021) Spiniello, C.; Tortora, C.; D'Ago, G.; Coccato, L.; La Barbera, F.; Ferre-Mateu, A.; Pulsoni, C.; Arnaboldi, M.; Gallazzi, A.; Hunt, L.; Napolitano, N. R.; Radovich, M.; Scognamiglio, D.; Spavone, M.; Zibetti, S.
Context. The INvestigating Stellar Population In RElics (INSPIRE) is an ongoing project targeting 52 ultra-compact massive galaxies at 0.1 < z < 0.5 with the X-shooter at VLT spectrograph (XSH). These objects are the ideal candidates to be `relics', massive red nuggets that have formed at high redshift (z > 2) through a short and intense star formation burst, and then have evolved passively and undisturbed until the present day. Relics provide a unique opportunity to study the mechanisms of star formation at high-z. Aims. INSPIRE is designed to spectroscopically confirm and fully characterise a large sample of relics, computing their number density in the redshift window 0:1 < z < 0:5 for the first time, thus providing a benchmark for cosmological galaxy formation simulations. In this paper, we present the INSPIRE Data Release (DR1), comprising 19 systems with observations completed in 2020. Methods. We use the methods already presented in the INSPIRE Pilot, but revisiting the 1D spectral extraction. For the 19 systems studied here, we obtain an estimate of the stellar velocity dispersion, fitting the two XSH arms (UVB and VIS) separately at their original spectral resolution to two spectra extracted in di fferent ways. We estimate [Mg /Fe] abundances via line-index strength and mass-weighted integrated stellar ages and metallicities with full spectral fitting on the combined (UVB +VIS) spectrum. Results. For each system, di fferent estimates of the velocity dispersion always agree within the errors. Spectroscopic ages are very old for 13 /19 galaxies, in agreement with the photometric ones, and metallicities are almost always (18 /19) super-solar, confirming the mass-metallicity relation. The [Mg /Fe] ratio is also larger than solar for the great majority of the galaxies, as expected. We find that ten objects formed more than 75% of their stellar mass (M-*) within 3 Gyr from the big bang and classify them as relics. Among these, we identify four galaxies that had already fully assembled their M-* by that time and are therefore `extreme relics' of the ancient Universe. Interestingly, relics, overall, have a larger [Mg /Fe] and a more metal-rich stellar population. They also have larger integrated velocity dispersion values compared to non-relics (both ultra-compact and normal-size) of similar stellar mass. Conclusions. The INSPIRE DR1 catalogue of ten known relics is the largest publicly available collection, augmenting the total number of confirmed relics by a factor of 3.3, and also enlarging the redshift window. The resulting lower limit for the number density of relics at 0.17 < z < 0.39 is rho similar to 9.1 x 10(-8) Mpc(-3).
INSPIRE: INvestigating Stellar Population In RElics III. Second data release (DR2): testing the systematics on the stellar velocity dispersion
(2023) D'Ago, G.; Spiniello, C.; Coccato, L.; Tortora, C.; La Barbera, F.; Arnaboldi, M.; Bevacqua, D.; Ferre-Mateu, A.; Gallazzi, A.; Hartke, J.; Hunt, L. K.; Martin-Navarro, I.; Napolitano, N. R.; Pulsoni, C.; Radovich, M.; Saracco, P.; Scognamiglio, D.; Zibetti, S.
Context. The project called INvestigating Stellar Population In RElics (INSPIRE) is based on VLT/X-shooter data from the homonymous on-going ESO Large Program. It targets 52 ultra-compact massive galaxies at 0.1 < z < 0.5 with the goal of constraining their kinematics and stellar population properties in great detail and of analysing their relic nature.
INSPIRE: INvestigating Stellar Population In RElics: I. Survey presentation and pilot study
(2021) Spiniello, C.; Tortora, C.; D'Ago, G.; Coccato, L.; La Barbera, F.; Ferre-Mateu, A.; Napolitano, N. R.; Spavone, M.; Scognamiglio, D.; Arnaboldi, M.; Gallazzi, A.; Hunt, L.; Moehler, S.; Radovich, M.; Zibetti, S.
Context. Massive elliptical galaxies are thought to form through a two-phase process. At early times (z> 2), an intense and fast starburst forms blue and disk-dominated galaxies. After quenching, the remaining structures become red, compact, and massive (i.e. red nuggets). Then, a time-extended second phase, which is dominated by mergers, causes structural evolution and size growth. Given the stochastic nature of mergers, a small fraction of red nuggets survive, without any interaction, massive and compact until today: these are relic galaxies. Since this fraction depends on the processes dominating the size growth, counting relics at low-z is a valuable way of disentangling between different galaxy evolution models.Aims. In this paper, we introduce the INvestigating Stellar Population In RElics (INSPIRE) Project, which aims to spectroscopically confirm and fully characterise a large number of relics at 0.1< z< 0.5. We focus here on the first results based on a pilot study targeting three systems, representative of the whole sample.Methods. For these three candidates, we extracted 1D optical spectra over an aperture of r=0.40 '', which comprises similar to 30% of the galaxies' light, and we obtained the line-of-sight integrated stellar velocity and velocity dispersion. We also inferred the stellar [alpha /Fe] abundance from line-index measurements and mass-weighted age and metallicity from full-spectral fitting with single stellar population models.Results. Two galaxies have large integrated stellar velocity dispersion values (sigma (star)similar to 250 km s(-1)), confirming their massive nature. They are populated by stars with super-solar metallicity and [alpha /Fe]. Both objects have formed >= 80% of their stellar mass within a short (similar to 0.5-1.0 Gyr) initial star formation episode occurred only similar to 1 Gyr after the Big Bang. The third galaxy has a more extended star formation history and a lower velocity dispersion. Thus we confirm two out of three candidates as relics.Conclusions. This paper is the first step towards assembling the final INSPIRE catalogue that will set stringent lower limits on the number density of relics at z< 0.5, thus constituting a benchmark for cosmological simulations, and their predictions on number densities, sizes, masses, and dynamical characteristics of these objects.
Larger and faster : revised properties and a shorter orbital period for the WASP-57 planetary system from a pro-am collaboration
(2015) Southworth, J.; Mancini, L.; Tregloan-Reed, J.; Novati, S.; Ciceri, S.; D'Ago, G.; Delrez, L.; Dominik, M.; Evans, D.; Rabus, Markus; Jehin, E.; Jorgensen, U.; Haugbolle, T.; Lend, M.; Arena, C.; Gillon, M.
OGLE-2014-BLG-1186 : gravitational microlensing providing evidence for a planet orbiting the foreground star or for a close binary source?
(2019) Dominik, M.; Bachelet, E.; Bozza, V.; Street, R.A.; Han, C.; Hundertmark, M.; Udalski, A.; Bramich, D.M; Alsubai, K.A.; Rabus, Markus; Novati, S.C.; Ciceri, S.; D'Ago, G.; Jaimes, R.F.; Haugbolle, T.; Hinse, T.C.; Horne, K.; Jorgensen, U.G.; Juncher, D.; Kains, N.; Korhonen, H.
Orbital alignment and star-spot properties in the WASP-52 planetary system
(OXFORD UNIV PRESS, 2017) Mancini, L.; Southworth, J.; Raia, G.; Tregloan Reed, J.; Molliere, P.; Bozza, V.; Bretton, M.; Bruni, I.; Ciceri, S.; D'Ago, G.; Dominik, M.; Hinse, T. C.; Hundertmark, M.; Jorgensen, U. G.; Korhonen, H.; Rabus, M.; Rahvar, S.; Starkey, D.; Novati, S. Calchi; Jaimes, R. Figuera; Henning, Th.; Juncher, D.; Haugbolle, T.; Kains, N.; Popovas, A.; Schmidt, R. W.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Wertz, O.
We report 13 high-precision light curves of eight transits of the exoplanet WASP-52 b, obtained by using four medium-class telescopes, through different filters, and adopting the defocussing technique. One transit was recorded simultaneously from two different observatories and another one from the same site but with two different instruments, including a multiband camera. Anomalies were clearly detected in five light curves and modelled as star-spots occulted by the planet during the transit events. We fitted the clean light curves with the JKTEBOP code, and those with the anomalies with the PRISM + GEMC codes in order to simultaneously model the photometric parameters of the transits and the position, size and contrast of each star-spot. We used these new light curves and some from the literature to revise the physical properties of the WASP-52 system. Star-spots with similar characteristics were detected in four transits over a period of 43 d. In the hypothesis that we are dealing with the same star-spot, periodically occulted by the transiting planet, we estimated the projected orbital obliquity of WASP-52 b to be. = 3 degrees.8 +/- 8 degrees.4. We also determined the true orbital obliquity, psi = 20 degrees +/- 50 degrees, which is, although very uncertain, the first measurement of. purely from star-spot crossings. We finally assembled an optical transmission spectrum of the planet and searched for variations of its radius as a function of wavelength. Our analysis suggests a flat transmission spectrum within the experimental uncertainties.
PATHWAY TO THE GALACTIC DISTRIBUTION OF PLANETS: COMBINED SPITZER AND GROUND-BASED MICROLENS PARALLAX MEASUREMENTS OF 21 SINGLE-LENS EVENTS
(2015) Novati, S. Calchi; Gould, A.; Udalski, A.; Menzies, J. W.; Bond, I. A.; Shvartzvald, Y.; Street, R. A.; Hundertmark, M.; Beichman, C. A.; Yee, J. C.; Carey, S.; Poleski, R.; Skowron, J.; Kozlowski, S.; Mroz, P.; Pietrukowicz, P.; Pietrzynski, G.; Szymanski, M. K.; Soszynski, I.; Ulaczyk, K.; Wyrzykowski, L.; Albrow, M.; Beaulieu, J. P.; Caldwell, J. A. R.; Cassan, A.; Coutures, C.; Danielski, C.; Prester, D. Dominis; Donatowicz, J.; Loncaric, K.; McDougall, A.; Morales, J. C.; Ranc, C.; Zhu, W.; Abe, F.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Fukunaga, D.; Inayama, K.; Koshimoto, N.; Namba, S.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Wakiyama, Y.; Yonehara, A.; Maoz, D.; Kaspi, S.; Friedmann, M.; Bachelet, E.; Jaimes, R. Figuera; Bramich, D. M.; Tsapras, Y.; Horne, K.; Snodgrass, C.; Wambsganss, J.; Steele, I. A.; Kains, N.; Bozza, V.; Dominik, M.; Jorgensen, U. G.; Alsubai, K. A.; Ciceri, S.; D'Ago, G.; Haugbolle, T.; Hessman, F. V.; Hinse, T. C.; Juncher, D.; Korhonen, H.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Schmidt, R. W.; Skottfelt, J.; Southworth, J.; Starkey, D.; Surdej, J.; Wertz, O.; Zarucki, M.; Gaudi, B. S.; Pogge, R. W.; De Poy, D. L.
We present microlens parallax measurements for 21 (apparently) isolated lenses observed toward the Galactic bulge that were imaged simultaneously from Earth and Spitzer, which was similar to 1 AU west of Earth in projection. We combine these measurements with a kinematic model of the Galaxy to derive distance estimates for each lens, with error bars that are small compared to the Sun's galactocentric distance. The ensemble therefore yields a well-defined cumulative distribution of lens distances. In principle, it is possible to compare this distribution against a set of planets detected in the same experiment in order to measure the Galactic distribution of planets. Since these Spitzer observations yielded only one planet, this is not yet possible in practice. However, it will become possible as larger samples are accumulated.
Physical properties of the planetary systemsWASP-45 and WASP-46 from simultaneous multiband photometry
(2016) Ciceri, S.; Mancini, L.; Southworth, J.; Lendl, M.; Tregloan Reed, J.; Brahm, R.; Chen, G.; D'Ago, G.; Rabus, Markus; Jordán Colzani, Andrés Cristóbal
Precision measurement of a brown dwarf mass in a binary system in the microlensing event OGLE-2019-BLG-0033/MOA-2019-BLG-035
(2022) Herald, A.; Udalski, A.; Bozza, V.; Rota, P.; Bond, I. A.; Yee, J. C.; Sajadian, S.; Mroz, P.; Poleski, R.; Skowron, J.; Szymanski, M. K.; Soszynski, I.; Pietrukowicz, P.; Kozlowski, S.; Ulaczyk, K.; Rybicki, K. A.; Iwanek, P.; Wrona, M.; Gromadzki, M.; Abe, F.; Barry, R.; Bennett, D. P.; Bhattacharya, A.; Fukui, A.; Fujii, H.; Hirao, Y.; Itow, Y.; Kirikawa, R.; Kondo, I.; Koshimoto, N.; Matsubara, Y.; Matsumoto, S.; Miyazaki, S.; Muraki, Y.; Olmschenk, G.; Ranc, C.; Okamura, A.; Rattenbury, N. J.; Satoh, Y.; Sumi, T.; Suzuki, D.; Silva, S. Ishitani; Toda, T.; Tristram, P. J.; Vandorou, A.; Yama, H.; Beichman, C. A.; Bryden, G.; Novati, S. Calchi; Carey, S.; Gaudi, B. S.; Gould, A.; Henderson, C. B.; Johnson, S.; Shvartzvald, Y.; Zhu, W.; Dominik, M.; Hundertmark, M.; Jorgensen, U. G.; Longa-Pena, P.; Skottfelt, J.; Tregloan-Reed, J.; Bach-Moller, N.; Burgdorf, M.; D'Ago, G.; Haikala, L.; Hitchcock, J.; Khalouei, E.; Peixinho, N.; Rahvar, S.; Snodgrass, C.; Southworth, J.; Spyratos, P.; Zang, W.; Yang, H.; Mao, S.; Bachelet, E.; Maoz, D.; Street, R. A.; Tsapras, Y.; Christie, G. W.; Cooper, T.; de Almeida, L.; do Nascimento, J. -D., Jr.; Green, J.; Han, C.; Hennerley, S.; Marmont, A.; McCormick, J.; Monard, L. A. G.; Natusch, T.; Pogge, R.
Context. Brown dwarfs are transition objects between stars and planets that are still poorly understood, for which several competing mechanisms have been proposed to describe their formation. Mass measurements are generally difficult to carry out for isolated objects as well as for brown dwarfs orbiting low-mass stars, which are often too faint for a spectroscopic follow-up.
Properties of intra-cluster low-mass X-ray binaries in Fornax globular clusters
(2022) Riccio, G.; Paolillo, M.; Cantiello, M.; D'Abrusco, R.; Jin, X.; Li, Z.; Puzia, T.; Mieske, S.; Prole, D. J.; Iodice, E.; D'Ago, G.; Gatto, M.; Spavone, M.
Aims. We present a study of the intra-cluster population of low-mass X-ray binaries (LMXB) residing in globular clusters (GC) in the central 1 deg(2) of the Fornax galaxy cluster. Differently from previous studies, which were restricted to the innermost regions of individual galaxies, this work is aimed at comparing the properties of the intra-cluster population of GC-LMXBs with those of the host galaxy. Methods. The data used in this work are a combination of the VLT Survey Telescope (VST) and Chandra observations. We performed a cross-match between the optical and the X-ray catalogue in order to identify the LMXBs residing in GCs. We divided the GC-LMXBs into host-galaxy and intra-cluster objects based on their distance from the nearest galaxy in terms of effective radius (R-eff). We found 82 intra-cluster GC-LMXBs and 86 objects that are hosted in galaxies. As the formation of LMXBs also depends on the host GC colour, we performed a Gaussian mixture model to divide the population into red and blue GCs. Results. As has been found for the innermost regions of galaxies, LMXBs tend to form in red and bright GCs in intra-cluster space as well. We find, however, that the likelihood of a red GC to host an LMXB decreases with galactocentric distance, but it remains approximately constant for the blue GC population. Investigating the X-ray properties of the LMXBs residing in GCs, we find a difference in the X-ray luminosity function between the intra-cluster and host-galaxy sample: both follow a power-law down to similar to 8.5 x 10(37) erg s(-1), which is consistent with field LMXBs for the intra-cluster sample, while the latter agree with previous estimates for LMXBs in GCs. We observe a deficiency of bright LMXBs in blue intra-cluster GCs, however. This might indicate a lack of black hole binaries in metal-poor systems. We further investigated the spectral properties of the GC-LMXBs through their hardness-ratio. We detect a tentative difference in the hardness ratio of two populations, where the intra-cluster GC-LMXBs appear to have harder spectra than the host-galaxy objects. We find the same trend when we compare red and blue GC-LMXBs: the spectra of the blue sample are harder spectra than those of the red sample. This result could suggest a relation between the spectral properties of LMXBs and the host GC colour and therefore its metallicity. We discuss the possibilities of spatial biases due to uncertainties in the X-ray spectral response correction and due to contamination by background active galactic nuclei.
Red noise versus planetary interpretations in the microlensing event OGLE-2013-BLG-446
(2015) Bachelet, E.; Bramich, D. M.; Han, C.; Greenhill, J.; Street, R. A.; Gould, A.; D'Ago, G.; AlSubai, K.; Dominik, M.; Rabus, Markus
Telltale signs of metal recycling in the circumgalactic medium of a z ∼ 0.77 galaxy
(2021) Tejos, N.; López, S.; Ledoux, C.; Fernández-Figueroa, A.; Rivas, N.; Sharon, K.; Johnston, E. J.; Florian, M. K.; D'Ago, G.; Katsianis, A.; Barrientos, F.; Berg, T.; Corro-Guerra, F.; Hamel, M.; Moya-Sierralta, C.; Poudel, S.; Rigby, J. R.; Solimano, M.
We present gravitational-arc tomography of the cool-warm enriched circumgalactic medium (CGM) of an isolated galaxy ('G1') at z approximate to 0.77. Combining VLT/MUSE adaptive-optics and Magellan/MagE echelle spectroscopy, we obtain partially resolved kinematics of Mg II in absorption and [O II] in emission. The unique arc configuration allows us to probe 42 spatially independent arc positions transverse to G1, plus four positions in front of it. The transverse positions cover G1's minor and major axes at impact parameters of approximate to 10-30 and approximate to 60kpc, respectively. We observe a direct kinematic connection between the cool-warm enriched CGM (traced by Mg II) and the interstellar medium (traced by [O II]). This provides strong evidence for the existence of an extended disc that co-rotates with the galaxy out to tens of kiloparsecs. The Mg II velocity dispersion (sigma approximate to 30-100 km s(-1), depending on position) is of the same order as the modelled galaxy rotational velocity (v(rot) approximate to 80 km s(-1)), providing evidence for the presence of a turbulent and pressure-supported CGM component. We regard the absorption to be modulated by a galactic-scale outflow, as it offers a natural scenario for the observed line-of-sight dispersion and asymmetric profiles observed against both the arcs and the galaxy. An extended enriched co-rotating disc together with the signatures of a galactic outflow, are telltale signs of metal recycling in the z similar to 1 CGM.
THE FIRST SIMULTANEOUS MICROLENSING OBSERVATIONS BY TWO SPACE TELESCOPES: SPITZER AND SWIFT REVEAL A BROWN DWARF IN EVENT OGLE-2015-BLG-1319
(2016) Shvartzvald, Y.; Li, Z.; Udalski, A.; Gould, A.; Sumi, T.; Street, R. A.; Novati, S. Calchi; Hundertmark, M.; Bozza, V.; Beichman, C.; Bryden, G.; Carey, S.; Drummond, J.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Tan, T. G.; Wibking, B.; Pogge, R. W.; Yee, J. C.; Zhu, W.; Tsapras, Y.; Bachelet, E.; Dominik, M.; Bramich, D. M.; Cassan, A.; Jaimes, R. Figuera; Horne, K.; Ranc, C.; Schmidt, R.; Snodgrass, C.; Wambsganss, J.; Steele, I. A.; Menzies, J.; Mao, S.; Poleski, R.; Pawlak, M.; Szymanski, M. K.; Skowron, J.; Mroz, P.; Kozlowski, S.; Wyrzykowski, L.; Pietrukowicz, P.; Soszynski, I.; Ulaczyk, K.; Abe, F.; Asakura, Y.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Bond, I. A.; Freeman, M.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Fukui, A.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Nishioka, T.; Ohnishi, K.; Oyokawa, H.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; Jorgensen, U. G.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Hinse, T. C.; Kains, N.; Kerins, E.; Korhonen, H.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Peixinho, N.; Verma, P.; Sbarufatti, B.; Kennea, J. A.; Gehrels, N.
Simultaneous observations of microlensing events from multiple locations allow for the breaking of degeneracies between the physical properties of the lensing system, specifically by exploring different regions of the lens plane and by directly measuring the "microlens parallax." We report the discovery of a 30-65M(J) brown dwarf orbiting a K dwarf in the microlensing event OGLE-2015-BLG-1319. The system is located at a distance of similar to 5 kpc toward the Galactic Bulge. The event was observed by several ground-based groups as well as by Spitzer and Swift, allowing a measurement of the physical properties. However, the event is still subject to an eight-fold degeneracy, in particular the well-known close-wide degeneracy, and thus the projected separation between the two lens components is either similar to 0.25 au or similar to 45 au. This is the first microlensing event observed by Swift, with the UVOT camera. We study the region of microlensing parameter space to which Swift is sensitive, finding that though Swift could not measure the microlens parallax with respect to ground-based observations for this event, it can be important for other events. Specifically, it is important for detecting nearby brown dwarfs and free-floating planets in high magnification events.
THE SPITZER MICROLENSING PROGRAM AS A PROBE FOR GLOBULAR CLUSTER PLANETS: ANALYSIS OF OGLE-2015-BLG-0448
(2016) Poleski, Radoslaw; Zhu, Wei; Christie, Grant W.; Udalski, Andrzej; Gould, Andrew; Bachelet, Etienne; Skottfelt, Jesper; Novati, Sebastiano Calchi; Szymanski, M. K.; Soszynski, I.; Pietrzynski, G.; Wyrzykowski, L.; Ulaczyk, K.; Pietrukowicz, P.; Kozlowski, Szymon; Skowron, J.; Mroz, P.; Pawlak, M.; Beichman, C.; Bryden, G.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Pogge, R. W.; Shvartzvald, Y.; Wibking, B.; Yee, J. C.; Beatty, T. G.; Eastman, J. D.; Drummond, J.; Friedmann, M.; Henderson, M.; Johnson, J. A.; Kaspi, S.; Maoz, D.; McCormick, J.; McCrady, N.; Natusch, T.; Ngan, H.; Porritt, I.; Relles, H. M.; Sliski, D. H.; Tan, T. G.; Wittenmyer, R. A.; Wright, J. T.; Street, R. A.; Tsapras, Y.; Bramich, D. M.; Horne, K.; Snodgrass, C.; Steele, I. A.; Menzies, J.; Jaimes, R. Figuera; Wambsganss, J.; Schmidt, R.; Cassan, A.; Ranc, C.; Mao, S.; Bozza, V.; Dominik, M.; Hundertmark, M. P. G.; Jorgensen, U. G.; Andersen, M. I.; Burgdorf, M. J.; Ciceri, S.; D'Ago, G.; Evans, D. F.; Gu, S. H.; Hinse, T. C.; Kains, N.; Kerins, E.; Korhonen, H.; Kuffmeier, M.; Mancini, L.; Popovas, A.; Rabus, M.; Rahvar, S.; Rasmussen, R. T.; Scarpetta, G.; Southworth, J.; Surdej, J.; Unda-Sanzana, E.; Verma, P.; von Essen, C.; Wang, Y. B.; Wertz, O.
The microlensing event OGLE-2015-BLG-0448 was observed by Spitzer and lay within the tidal radius of the globular cluster NGC 6558. The event had moderate magnification and was intensively observed, hence it had the potential to probe the distribution of planets in globular clusters. We measure the proper motion of NGC 6558 (mu(cl) (N, E) = (+0.36 +/- 0.10, +1.42 +/- 0.10) mas yr(-1)) as well as the source and show that the lens is not a cluster member. Even though this particular event does not probe the distribution of planets in globular clusters, other potential cluster lens events can be verified using our methodology. Additionally, we find that microlens parallax measured using Optical Gravitational Lens Experiment (OGLE) photometry is consistent with the value found based on the light curve displacement between the Earth and Spitzer.

Browsing by Author "D'Ago, G."

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