Neurotoxic reactive astrocytes are induced by activated microglia

Liddelow, Shane A.,Guttenplan, Kevin A.,Clarke, Laura E.,Bennett, Frederick C.,Bohlen, Christopher J.,Schirmer, Lucas,Bennett, Mariko L.,Mü,nch, Alexandra E.,Chung, Won-Suk,Peterson, Todd C.,Wilto Nature Publishing Group, a division of Macmillan P 2017 Nature Vol.541 No.7638

<P>Reactive astrocytes are strongly induced by central nervous system (CNS) injury and disease, but their role is poorly understood. Here we show that a subtype of reactive astrocytes, which we termed A1, is induced by classically activated neuroinflammatory microglia. We show that activated microglia induce A1 astrocytes by secreting Il-1 alpha, TNF and C1q, and that these cytokines together are necessary and sufficient to induce A1 astrocytes. A1 astrocytes lose the ability to promote neuronal survival, outgrowth, synaptogenesis and phagocytosis, and induce the death of neurons and oligodendrocytes. Death of axotomized CNS neurons in vivo is prevented when the formation of A1 astrocytes is blocked. Finally, we show that A1 astrocytes are abundant in various human neurodegenerative diseases including Alzheimer's, Huntington's and Parkinson's disease, amyotrophic lateral sclerosis and multiple sclerosis. Taken together these findings help to explain why CNS neurons die after axotomy, strongly suggest that A1 astrocytes contribute to the death of neurons and oligodendrocytes in neurodegenerative disorders, and provide opportunities for the development of new treatments for these diseases.</P>

REVISITING THE MICROLENSING EVENT OGLE 2012-BLG-0026: A SOLAR MASS STAR WITH TWO COLD GIANT PLANETS

Beaulieu, J.-P.,Bennett, D. P.,Batista, V.,Fukui, A.,Marquette, J.-B.,Brillant, S.,Cole, A. A.,Rogers, L. A.,Sumi, T.,Abe, F.,Bhattacharya, A.,Koshimoto, N.,Suzuki, D.,Tristram, P. J.,Han, C.,Gould, A American Astronomical Society 2016 The Astrophysical Journal Vol.824 No.2

<P>Two cold gas giant planets orbiting a G-type main-sequence star in the galactic disk were previously discovered in the high-magnification microlensing event OGLE-2012-BLG-0026. Here, we present revised host star flux measurements and a refined model for the two-planet system using additional light curve data. We performed high angular resolution adaptive optics imaging with the Keck and Subaru telescopes at two epochs while the source star was still amplified. We detected the lens flux, H = 16.39 +/- 0.08. The lens, a disk star, is brighter than predicted from the modeling in the original study. We revisited the light curve modeling using additional photometric data from the B&C telescope in New Zealand and CTIO 1.3 m H-band light curve. We then include the Keck and Subaru adaptive optic observation constraints. The system is composed of a similar to 4-9 Gyr lens star of M-lens = 1.06 +/- 0.05 M circle dot at a distance of D-lens = 4.0 +/- 0.3 kpc, orbited by two giant planets of 0.145 +/- 0.008 M-Jup and 0.86 +/- 0.06 M-Jup, with projected separations of 4.0 +/- 0.5 au and 4.8 +/- 0.7 au, respectively. Because the lens is brighter than the source star by 16 +/- 8% in H, with no other blend within one arcsec, it will be possible to estimate its metallicity using subsequent IR spectroscopy with 8-10 m class telescopes. By adding a constraint on the metallicity it will be possible to refine the age of the system.</P>

OGLE-2012-BLG-0563Lb: A SATURN-MASS PLANET AROUND AN M DWARF WITH THE MASS CONSTRAINED BY<i>SUBARU</i>AO IMAGING

Fukui, A.,Gould, A.,Sumi, T.,Bennett, D. P.,Bond, I. A.,Han, C.,Suzuki, D.,Beaulieu, J.-P.,Batista, V.,Udalski, A.,Street, R. A.,Tsapras, Y.,Hundertmark, M.,Abe, F.,Bhattacharya, A.,Freeman, M.,Itow, IOP Publishing 2015 The Astrophysical journal Vol.809 No.1

<P>We report the discovery of a microlensing exoplanet OGLE-2012-BLG-0563Lb with the planet-star mass ratio of similar to 1 x 10(-3). Intensive photometric observations of a high-magnification microlensing event allow us to detect a clear signal of the planet. Although no parallax signal is detected in the light curve, we instead succeed at detecting the flux from the host star in high-resolution JHK'-band images obtained by the Subaru/AO188 and Infrared Camera and Spectrograph instruments, allowing us to constrain the absolute physical parameters of the planetary system. With the help of spectroscopic information about the source star obtained during the high-magnification state by Bensby et al., we find that the lens system is located at 1.3(-0.8)(+0.6) kpc from us, and consists of an M dwarf (0.34(-0.20)(+0.12)M(circle dot)) orbited by a Saturn-mass planet (0.39(-0.23)(+0.14)M(Jup)) at the projected separation of 0.74(-0.42)(+0.26)AU (close model) or 4.3(-2.5)(+1.5)AU (wide model). The probability of contamination in the host star's flux, which would reduce the masses by a factor of up to three, is estimated to be 17%. This possibility can be tested by future high-resolution imaging. We also estimate the (J - K-s) and (H - K-s) colors of the host star, which are marginally consistent with a low metallicity mid-to-early M dwarf, although further observations are required for the metallicity to be conclusive. This is the fifth sub-Jupiter-mass (0.2 < m(p)/M-Jup < 1) microlensing planet around an M dwarf with the mass well constrained. The relatively rich harvest of sub-Jupiters around M dwarfs is contrasted with a possible paucity of similar to 1-2 Jupiter-mass planets around the same type of star, which can be explained by the planetary formation process in the core-accretion scheme.</P>

THE FIRST NEPTUNE ANALOG OR SUPER-EARTH WITH A NEPTUNE-LIKE ORBIT: MOA-2013-BLG-605LB

Sumi, T.,Udalski, A.,Bennett, D. P.,Gould, A.,Poleski, R.,Bond, I. A.,Skowron, J.,Rattenbury, N.,Pogge, R. W.,Bensby, T.,Beaulieu, J. P.,Marquette, J. B.,Batista, V.,Brillant, S.,Abe, F.,Asakura, Y.,B American Astronomical Society 2016 The Astrophysical journal Vol.825 No.2

<P>We present the discovery of the first Neptune analog exoplanet or super-Earth with a Neptune-like orbit, MOA-2013-BLG-605Lb. This planet has a mass similar to that of Neptune or a super-Earth and it orbits at 9 similar to 14 times the expected position of the snow line, a(snow), which is similar to Neptune's separation of 11 a(snow) from the Sun. The planet/host-star mass ratio is q = (3.6 +/- 0.7) x 10(-4) and the projected separation normalized by the Einstein radius is s = 2.39 +/- 0.05. There are three degenerate physical solutions and two of these are due to a new type of degeneracy in the microlensing parallax parameters, which we designate 'the wide degeneracy.' The three models have (i) a Neptune-mass planet with a mass of M-p = 21(-7)(+6)M(circle plus) orbiting a low-mass M-dwarf with a mass of M-h = 0.19(-0.06)(+0.05)M(circle dot), (ii) a mini-Neptune with M-p = 7.9(-1.2)(+1.8)M(circle plus) orbiting a brown dwarf host with M-h = 0.068(-0.011)(+0.019)M(circle dot), and (iii) a super-Earth with M-p = 3.2(-0.3)(+0.5)M(circle plus) orbiting a low-mass brown dwarf host with M-h = 0.025(-0.004)(+0.005)M(circle dot), which is slightly favored. The 3D planet-host separations are 4.6(-1.2)(+4.7) au, 2.1(-0.2) (+1.0) au, and 0.94(-0.02)(+0.67) au, which are 8.9(-1.4)(+10.5), 12(-1)(+7), or 14(-1)(+11) times larger than a(snow) for these models, respectively. Keck adaptive optics observations confirm that the lens is faint. This discovery suggests that low-mass planets with Neptune-like orbits are common. Therefore processes similar to the one that formed Neptune in our own solar system or cold super-Earths may be common in other solar systems.</P>

A POSSIBLE BINARY SYSTEM OF A STELLAR REMNANT IN THE HIGH-MAGNIFICATION GRAVITATIONAL MICROLENSING EVENT OGLE-2007-BLG-514

Miyake, N.,Udalski, A.,Sumi, T.,Bennett, D. P.,Dong, S.,Street, R. A.,Greenhill, J.,Bond, I. A.,Gould, A.,Kubiak, M.,Szymań,ski, M. K.,Pietrzyń,ski, G.,Soszyń,ski, I.,Ulaczyk, K.,Wyrzyk IOP Publishing 2012 The Astrophysical journal Vol.752 No.2

<P>We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 +/- 0.007 and a projected separation of s = 0.072 +/- 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D-L = 3.11 +/- 0.39 kpc and total mass M-L = 1.40 +/- 0.18 M-circle dot; this leads to the primary and secondary components having masses of M-1 = 1.06 +/- 0.13 M-circle dot and M-2 = 0.34 +/- 0.04 M-circle dot, respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 +/- 0.005, s = 0.083 +/- 0.001). The primary component of the binary lens is relatively massive, with M-1 = 0.9(-0.3)(+4.6) M-circle dot and it is at a distance of D-L = 2.6(-0.9)(+3.8) kpc. Given the secure mass ratio measurement, the companion mass is therefore M-2 = 0.2(-0.1)(+1.2) M-circle dot. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.</P>

A SUB-SATURN MASS PLANET, MOA-2009-BLG-319Lb

Miyake, N.,Sumi, T.,Dong, Subo,Street, R.,Mancini, L.,Gould, A.,Bennett, D. P.,Tsapras, Y.,Yee, J. C.,Albrow, M. D.,Bond, I. A.,Fouqué,, P.,Browne, P.,Han, C.,Snodgrass, C.,Finet, F.,Furusawa, K IOP Publishing 2011 The Astrophysical journal Vol.728 No.2

<P>We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K-or M-dwarf star in the inner Galactic disk or Galactic bulge. The high-cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high-magnification event approximately 24 hr prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 +/- 0.02) x 10(-4) and a separation of d = 0.97537 +/- 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t(E), and angular Einstein radius,theta(E), along with a standard Galactic model indicates a host star mass of M-L = 0.38(-0.18)(+0.34) M-circle dot and a planet mass of M-p = 50(-24)(+44)M(circle plus), which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4(-0.6)(+1.2) AU and a distance to the planetary system of D-L = 6.1(-1.2)(+1.1) kpc. This separation is similar to 2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing.</P>

MASSES AND ORBITAL CONSTRAINTS FOR THE OGLE-2006-BLG-109Lb,c JUPITER/SATURN ANALOG PLANETARY SYSTEM

Bennett, D. P.,Rhie, S. H.,Nikolaev, S.,Gaudi, B. S.,Udalski, A.,Gould, A.,Christie, G. W.,Maoz, D.,Dong, S.,McCormick, J.,Szymań,ski, M. K.,Tristram, P. J.,Macintosh, B.,Cook, K. H.,Kubiak, M.,P IOP Publishing 2010 The Astrophysical journal Vol.713 No.2

<P>We present a new analysis of the Jupiter+Saturn analog system, OGLE-2006-BLG-109Lb,c, which was the first double planet system discovered with the gravitational microlensing method. This is the only multi-planet system discovered by any method with measured masses for the star and both planets. In addition to the signatures of two planets, this event also exhibits a microlensing parallax signature and finite source effects that provide a direct measure of the masses of the star and planets, and the expected brightness of the host star is confirmed by Keck AO imaging, yielding masses of M(*) = 0.51(-0.04)(+0.05) M(circle dot), M(b) = 231 +/- 19 M(circle plus), and M(c) = 86 +/- 7 M(circle plus). The Saturn-analog planet in this system had a planetary light-curve deviation that lasted for 11 days, and as a result, the effects of the orbital motion are visible in the microlensing light curve. We find that four of the six orbital parameters are tightly constrained and that a fifth parameter, the orbital acceleration, is weakly constrained. No orbital information is available for the Jupiter-analog planet, but its presence helps to constrain the orbital motion of the Saturn-analog planet. Assuming co-planar orbits, we find an orbital eccentricity of epsilon = 0.15(-0.10) (+0.17) and an orbital inclination of i = 64 degrees(+ 4 degrees)(-7 degrees) The 95% confidence level lower limit on the inclination of i > 49 degrees implies that this planetary system can be detected and studied via radial velocity measurements using a telescope of greater than or similar to 30 m aperture.</P>

INTERPRETATION OF A SHORT-TERM ANOMALY IN THE GRAVITATIONAL MICROLENSING EVENT MOA-2012-BLG-486

Hwang, K.-H.,Choi, J.-Y.,Bond, I. A.,Sumi, T.,Han, C.,Gaudi, B. S.,Gould, A.,Bozza, V.,Beaulieu, J.-P.,Tsapras, Y.,Abe, F.,Bennett, D. P.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Fukunaga, D.,Ha IOP Publishing 2013 The Astrophysical journal Vol.778 No.1

<P>A planetary microlensing signal is generally characterized by a short-term perturbation to the standard single lensing light curve. A subset of binary-source events can produce perturbations that mimic planetary signals, thereby introducing an ambiguity between the planetary and binary-source interpretations. In this paper, we present the analysis of the microlensing event MOA-2012-BLG-486, for which the light curve exhibits a short-lived perturbation. Routine modeling not considering data taken in different passbands yields a best-fit planetary model that is slightly preferred over the best-fit binary-source model. However, when allowed for a change in the color during the perturbation, we find that the binary-source model yields a significantly better fit and thus the degeneracy is clearly resolved. This event not only signifies the importance of considering various interpretations of short-term anomalies, but also demonstrates the importance of multi-band data for checking the possibility of false-positive planetary signals.</P>

MOA-2011-BLG-293Lb: A TEST OF PURE SURVEY MICROLENSING PLANET DETECTIONS

Yee, J. C.,Shvartzvald, Y.,Gal-Yam, A.,Bond, I. A.,Udalski, A.,Kozłowski, S.,Han, C.,Gould, A.,Skowron, J.,Suzuki, D.,Abe, F.,Bennett, D. P.,Botzler, C. S.,Chote, P.,Freeman, M.,Fukui, A.,Furusawa, K. IOP Publishing 2012 The Astrophysical journal Vol.755 No.2

<P>Because of the development of large-format, wide-field cameras, microlensing surveys are now able to monitor millions of stars with sufficient cadence to detect planets. These new discoveries will span the full range of significance levels including planetary signals too small to be distinguished from the noise. At present, we do not understand where the threshold is for detecting planets. MOA-2011-BLG-293Lb is the first planet to be published from the new surveys, and it also has substantial follow-up observations. This planet is robustly detected in survey+follow-up data (Delta chi(2) similar to 5400). The planet/host mass ratio is q = (5.3 similar to 0.2) x 10(-3). The best-fit projected separation is s = 0.548 +/- 0.005 Einstein radii. However, due to the s <-> s(-1) degeneracy, projected separations of s-1 are only marginally disfavored at Delta chi(2) = 3. A Bayesian estimate of the host mass gives M-L = 0.43(-0.17)(+0.27) M-circle dot, with a sharp upper limit of M-L < 1.2 M-circle dot from upper limits on the lens flux. Hence, the planet mass is m(p) = 2.4(-0.9)(+1.5) M-Jup, and the physical projected separation is either r(perpendicular to) similar or equal to 1.0 AU or r(perpendicular to) similar or equal to 3.4 AU. We show that survey data alone predict this solution and are able to characterize the planet, but the Delta chi(2) is much smaller (Delta chi(2) similar to 500) than with the follow-up data. The Delta chi(2) for the survey data alone is smaller than for any other securely detected planet. This event suggests a means to probe the detection threshold, by analyzing a large sample of events like MOA-2011-BLG-293, which have both follow-up data and high-cadence survey data, to provide a guide for the interpretation of pure survey microlensing data.</P>

OGLE-2011-BLG-0265Lb: A JOVIAN MICROLENSING PLANET ORBITING AN M DWARF

Skowron, J.,Shin, I.-G.,Udalski, A.,Han, C.,Sumi, T.,Shvartzvald, Y.,Gould, A.,Dominis Prester, D.,Street, R. A.,Jørgensen, U. G.,Bennett, D. P.,Bozza, V.,Szymań,ski, M. K.,Kubiak, M.,Pietrzy
IOP Publishing 2015 The Astrophysical journal Vol.804 No.1

<P>We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies of planetary formation and evolution. High-cadence temporal coverage of the planetary signal, combined with extended observations throughout the event, allows us to accurately model the observed light curve. However, the final microlensing solution remains degenerate, yielding two possible configurations of the planet and the host star. In the case of the preferred solution, the mass of the planet is M-p = 0.9 +/- 0.3 M-J, and the planet is orbiting a star with a mass M = 0.22 +/- 0.06 M-circle dot. The second possible configuration (2 sigma away) consists of a planet with M-p = 0.6 +/- 0.3M(J) and host star with M = 0.14 +/- 0.06M(circle dot). The system is located in the Galactic disk 3-4 kpc toward the Galactic bulge. In both cases, with an orbit size of 1.5-2.0 AU, the planet is a 'cold Jupiter'-located well beyond the 'snow line' of the host star. Currently available data make the secure selection of the correct solution difficult, but there are prospects for lifting the degeneracy with additional follow-up observations in the future, when the lens and source star separate.</P>