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Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: Left: WD 0310–688 at 21 μm in each of the four dithers. Center: PSF subtraction at each of the four dithers. Note that the cosmic ray in the first dither and the negative source at a ∼30 pixel separation is in the reference star image, not the science image. Right: PSF subtraction after a companion that is 21% of the brightness of the star was injected at 2.3 au. This injected source is retrieved with a statistical significance of 7.0σ (at each dither, the significance of the detections are 3.2σ, 4.2σ, 3.7σ, and 2.7σ). Injected sources are successfully retrieved at >4σ when injected at separations of >2 au; therefore, we constrain the detected IR excess source to be within 2 au of the host.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: Evolution of the stellar radius as a function of age for a 1.9 M ⊙ star, simulated using MESA Isochrones & Stellar Tracks (MESA version v7503). The pink shaded region represents the range of possible orbital separations of the planetary companion (0.1–2 au). The dotted lines mark the bounds of this range. The maximum radius reached by the star at the tip of the RGB (2.1 au) exceeds even the most generous estimate of the orbital separation, indicating that the planetary companion likely falls into the forbidden zone.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: Constraints on the planets orbiting WD 0310–688 from astrometry. We overplot the planetary parameters implied by the infrared excess, assuming that the upper limit in projected separation translates to semimajor axis. The absence of a large Gaia DR3 RUWE helps to exclude the more distant, massive edge of the parameter space, but within a < 1 au, the sensitivity of astrometry is low. At larger distances (2.5–10 au), planets with masses as low as 1 M Jup can be ruled ruled out due to the absence of a significant Hipparcos–Gaia acceleration.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: Measured wavelength-dependent infrared excess (i.e., the planet-to-star flux ratio, if the source of the infrared excess is a planet) from three photometric bands collected with JWST MIRI (F770W, F1800W, and F2100W). The infrared excess is consistent with a blackbody of temperature ﹩{248}_{-61}^{+84}﹩ K and an emitting area of ﹩{1.03}_{-0.35}^{+0.67}﹩                         R Jup. Using the derived system age, the planet’s temperature, and planet cooling curves, we estimate a planet mass of ﹩{3.0}_{-1.9}^{+5.5}﹩                         M Jup.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: In a reanalysis of an archival HST/STIS spectrum of WD 0310–688, we detect atomic lines of four metals in the white dwarf's photosphere. This suggests accretion of metal-rich material onto the white dwarf, and we reclassify it as a DAZ due to the presence of the metal lines. WD 0310–688 previously was a DA spectral type.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: Posterior of the disk inclination from the Jura disk model fit (upper left) and a schematic of the disk viewed at 88.°21 (bottom) and face-on (upper right) for comparison.
Paper: Theoretical Modeling of the Exceptional GRB 221009A Afterglow
Authors: Luca Foffano, Marco Tavani, Giovanni Piano
Figure caption: Calculated SEDs (as in Figure 2) for the time intervals T 1, T 2, T 3, and T 4. We show simultaneous data from AGILE GRID (red circles) and LHAASO (blue squares). AGILE MCAL data at ﹩t^{\prime} =[167:256]﹩ s are shown in gray in (b). In the T 4 interval, also X-ray and hard X-ray data from Swift-XRT (orange squares) in ﹩t^{\prime} =[3174:4274]﹩ s and BAT (violet diamond) in ﹩t^{\prime} =[3674:4301]﹩ s are reported.
Paper: Theoretical Modeling of the Exceptional GRB 221009A Afterglow
Authors: Luca Foffano, Marco Tavani, Giovanni Piano
Figure caption: SEDs calculated for the time intervals T −1 and T 0, with parameters reported in Table 1. The overall SSC emission (continuous thick line) is given by synchrotron (black dashed) and inverse-Compton (black dotted) contributions. The TeV SSC emission without γ γ internal absorption is shown with a dashed gray line, and the EBL absorbed emission is shown with a dashed–dotted gray line LHAASO data points are reported in blue squares—both the observed data (filled) and the EBL deabsorbed data (empty). The corresponding butterflies are related to the statistical error (dark blue region) and to the additional error due to the EBL deabsorption process (light blue region). AGILE MCAL data at ﹩t^{\prime} =[-15:-3]﹩ s are shown in gray in (a).
Paper: Theoretical Modeling of the Exceptional GRB 221009A Afterglow
Authors: Luca Foffano, Marco Tavani, Giovanni Piano
Figure caption: Flux intensity lightcurves of the GRB 221009A afterglow for different energy bands. We include optical data (pink diamonds), X-ray data (orange triangles), GeV data (red squares), and TeV data (blue circles). We indicate the relevant time intervals considered in our analysis as given in Table 1. We also define four main phases of the afterglow (very early, early, late, and very late).
Paper: Cautionary Tales on Heating-rate Prescriptions in Kilonovae
Authors: Nikhil Sarin, Stephan Rosswog
Figure caption: Set of lightcurves for different Vera Rubin Observatory filters with a two-component kilonova model for different ejecta velocities and electron fractions (other parameters are identical). For all three models, we fix the ejecta masses of each component to 0.02 and 0.04 M ⊙, and floor temperatures to 1500 and 500 K, respectively, to isolate the impact of the heating rate. The blue and green curves show two-component ejecta with electron fractions of 0.35, 0.05, 0.25, and 0.1, while the red curves show both components for an electron fraction of 0.4. For the ejecta velocities, we fix the first component velocity to 0.05c for the blue and red curves and 0.25c for the green curve. The second component velocities are 0.1, 0.05, and 0.15c, for the blue, green, and red curves, respectively. The old heating-rate prescription (O. Korobkin et al. 2012) is shown as dashed curves, while the solid curves show the updated prescription (S. Rosswog & O. Korobkin 2024). The physics behind the two models is the same apart from the heating-rate prescription.
Paper: The Origin of the Coherent Radio Flash Potentially Associated with GRB 201006A
Authors: Nikhil Sarin, Teagan A. Clarke, Spencer J. Magnall, Paul D. Lasky, Brian D. Metzger, Edo Berger, Navin Sridhar
Figure caption: X-ray afterglow data of GRB 201006A (assuming z = 0.58) with binning consistent with A. Rowlinson et al. (2023) in the left panel and Swift automatic binning on the right panel. The left panel shows 100 random draws (red curves) from the posterior of a fit with a magnetar and power-law model, while the right panel shows the same but with just the power-law model. In the left panel, we also include the inferred luminosity of the magnetar itself (blue curves). The gray vertical line indicates the time of the radio flash.
Paper: The Origin of the Coherent Radio Flash Potentially Associated with GRB 201006A
Authors: Nikhil Sarin, Teagan A. Clarke, Spencer J. Magnall, Paul D. Lasky, Brian D. Metzger, Edo Berger, Navin Sridhar
Figure caption:  R-band (left) and i-band (right) light curves for a magnetar-driven kilonova for two different types of magnetar engines at z = 0.58: one where the bulk of the rotational energy thermalizes the ejecta (blue curves) and another where the rotational energy is instead used in accelerating the ejecta (red curves). The arrows indicate the upper limit set by follow-up observations of GRB 201006A. The solid curves are for an engine with a spin period of 0.7 ms, whereas the dashed curves are for an engine with a slower initial spin period of 2 ms.
Paper: The Origin of the Coherent Radio Flash Potentially Associated with GRB 201006A
Authors: Nikhil Sarin, Teagan A. Clarke, Spencer J. Magnall, Paul D. Lasky, Brian D. Metzger, Edo Berger, Navin Sridhar
Figure caption: Kilonova afterglow at 1.4 GHz for the same magnetar parameters as in Figure 3, the width of the bands indicates the uncertainty in the kilonova afterglow for ambient interstellar medium densities between (10−4–10−2 cm−3). The horizontal solid and dashed bands indicate the detection limits of the VLA and Meerkat, respectively.
Paper: The Origin of the Coherent Radio Flash Potentially Associated with GRB 201006A
Authors: Nikhil Sarin, Teagan A. Clarke, Spencer J. Magnall, Paul D. Lasky, Brian D. Metzger, Edo Berger, Navin Sridhar
Figure caption: Schematic showing the possible outcomes of a binary neutron star merger that could create the coherent radio emission seen in GRB 201006A after 49 minutes (in the source frame at z = 0.58).
Paper: Cautionary Tales on Heating-rate Prescriptions in Kilonovae
Authors: Nikhil Sarin, Stephan Rosswog
Figure caption: 95% credible interval from 5000 simulated kilonovae with fixed ejecta masses and temperature floors and varying velocities and opacities for old prescription in blue and updated prescription in green.
Paper: Cavitating Bubbles in Condensing Gas as a Means of Forming Clumps, Chondrites, and Planetesimals
Authors: E. Chiang
Figure caption: A cavitating bubble of silicate/metal vapor and dust (no H2 anywhere), set against the backdrop of an impact plume generated by a vaporizing collision between asteroids (e.g., N. Choksi et al. 2021), could form a chondritic parent body. Here an R = 1 km sized bubble starts optically thick at t = 0 (top left and right panels), with M solid/M = 1/3 of its mass in s = 10 μm sized dust grains and the remaining 2/3 in saturated silicate vapor. The bubble resides in a radiation bath whose temperature T rad,bkg is a few percent lower than the bubble’s (bottom left panel), allowing the bubble to radiate energy to the background and ultimately collapse after t ≃ 10 minutes. Collapse speeds vary up to ∼20 m s−1 (top left panel), fast enough to overcome background flows (estimated to have a magnitude of ≲0.3 m s−1 on R ≲ 1 km scales; see main text) trying to shear the bubble apart. Embedded particles chondrule sized or smaller, with sizes s  c  ≤ 1 mm, compactify with the bubble (bottom right panel), while centimeter-sized and larger particles are too heavy to be dragged by gas and are left behind. Particle relative velocities are expected to be less than ﹩\max | \dot{R}| \simeq 20﹩ m s−1, slow enough that colliding particles may not shatter (L. L. Hood & F. J. Ciesla 2001; G. Wurm et al. 2005; J. Teiser & G. Wurm 2009; L. A. J. Garvie et al. 2017). Compactified to solid density (ρ solid = 3 g cm−3), the bubble would produce a planetesimal of radius 9 m.
Paper: The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf
Authors: Mary Anne Limbach, Andrew Vanderburg, Alexander Venner, Simon Blouin, Kevin B. Stevenson, Ryan J. MacDonald, Sydney Jenkins, Rachel Bowens-Rubin, Melinda Soares-Furtado, Caroline Morley, Markus Janson, John Debes, Siyi Xu, Evangelia Kleisioti, Matthew Kenworthy, Paul Butler, Jeffrey D. Crane, Dave Osip, Stephen Shectman, Johanna Teske
Figure caption: False-color image of WD 0310–688 (bluish-white star in the center) using three JWST/MIRI bands: F770W (blue), F1800W (green), and F2100W (red). Other sources in the field include distant galaxies, background stars, and potentially a few point sources that could be wide-orbit exoplanets bound to WD 0310–688. Although not the main focus of this Letter, we note the very faint source 80 au above the white dwarf, which is marginally detected at 18 and 21 μm, consistent with a T eff ∼ 140 K planet slightly less massive than Jupiter; however, at this separation, the false-positive rate is reasonably high. Confirming any resolved sources as bound exoplanets would necessitate follow-up observations for common proper motion at a later epoch.
Paper: Redshifted Sodium Transient near Exoplanet Transit
Authors: Apurva V. Oza, Julia V. Seidel, H. Jens Hoeijmakers, Athira Unni, Aurora Y. Kesseli, Carl A. Schmidt, Thirupathi Sivarani, Aaron Bello-Arufe, Andrea Gebek, Moritz Meyer zu Westram, Sérgio G. Sousa, Rosaly M. C. Lopes, Renyu Hu, Katherine de Kleer, Chloe Fisher, Sébastien Charnoz, Ashley D. Baker, Samuel P. Halverson, Nick M. Schneider, Angelica Psaridi, Aurélien Wyttenbach, Santiago Torres, Ishita Bhatnagar, Robert E. Johnson
Figure caption: Four-panel Gaussian fit runs for a nominal sodium absorption solution where ﹩{f}_{{{\rm{D}}}_{2}/{{\rm{D}}}_{1}}=1.0﹩. (a) Epoch I: 2015 December 6; (b) Epoch II: 2015 December 31; (c) Epoch III: 2016 January 14; (d) Epoch IV: 2020 December 15. Posterior distributions of the model parameters describe the Na doublet as a pair of Gaussians with the same amplitude dF Na/F ⋆, centroid velocity shift v 0, width σ, and continuum c. The uncertainties are scaled with β, which is a free fitting parameter.
Paper: Redshifted Sodium Transient near Exoplanet Transit
Authors: Apurva V. Oza, Julia V. Seidel, H. Jens Hoeijmakers, Athira Unni, Aurora Y. Kesseli, Carl A. Schmidt, Thirupathi Sivarani, Aaron Bello-Arufe, Andrea Gebek, Moritz Meyer zu Westram, Sérgio G. Sousa, Rosaly M. C. Lopes, Renyu Hu, Katherine de Kleer, Chloe Fisher, Sébastien Charnoz, Ashley D. Baker, Samuel P. Halverson, Nick M. Schneider, Angelica Psaridi, Aurélien Wyttenbach, Santiago Torres, Ishita Bhatnagar, Robert E. Johnson
Figure caption: Transmission spectrum of neutral atomic sodium (Na I) over four epochs, with raw data (blue), posterior model (orange), and median fit (red). (a) Epoch I: 2015 December 6; (b) Epoch II: 2015 December 31; (c) Epoch III: 2016 January 14; (d) Epoch IV: 2020 December 15 (ESPRESSO/VLT). The Epoch II net Doppler shift is measured to be a redshift v0 = +9.7 ± 1.6 km s−1. Epoch III is a nondetection. In Epoch I, a blueshift is seen, at low significance. Companion residual lightcurves for each epoch are provided (Figure 3).
Paper: Redshifted Sodium Transient near Exoplanet Transit
Authors: Apurva V. Oza, Julia V. Seidel, H. Jens Hoeijmakers, Athira Unni, Aurora Y. Kesseli, Carl A. Schmidt, Thirupathi Sivarani, Aaron Bello-Arufe, Andrea Gebek, Moritz Meyer zu Westram, Sérgio G. Sousa, Rosaly M. C. Lopes, Renyu Hu, Katherine de Kleer, Chloe Fisher, Sébastien Charnoz, Ashley D. Baker, Samuel P. Halverson, Nick M. Schneider, Angelica Psaridi, Aurélien Wyttenbach, Santiago Torres, Ishita Bhatnagar, Robert E. Johnson
Figure caption: HARPS/ESPRESSO neutral sodium residual lightcurves (d λ = 0.75 Å). Black data points are Na D2 spectra at four epochs centered at the transit of the hot Saturn WASP-49 A b, t 0,exoplanet. Yellow bands mark one-half of the Hill sphere transit time, and blue bands mark the t 1 − t 4 exoplanet transit time.
Paper: A Hide-and-seek Game: Looking for Population III Stars during the Epoch of Reionization through the He II λ1640 Line
Authors: Alessandra Venditti, Volker Bromm, Steven L. Finkelstein, Antonello Calabrò, Lorenzo Napolitano, Luca Graziani, Raffaella Schneider
Figure caption: Average He II line luminosity (L HeII, shaded regions) arising from Pop III-hosting dustyGadget galaxies at z ∼ 6.7–10, assuming a Salpeter-like IMF in the range [100, 500] M ⊙, compared with available observational candidates, i.e., LAP1 at z ≃ 6.6 (E. Vanzella et al. 2023, purple stars), RXJ2129-z8HeII at z ≃ 8.2 (X. Wang et al. 2024, green star), and GN-z11 at z ≃ 10.6 (R. Maiolino et al. 2024, blue stars). The dark red/dark cyan shaded regions refer to the models assuming no/strong mass loss (No ML/Strong ML), respectively, with variable Pop III formation efficiency η III from 0.01 (lower end of the regions) to 0.3 (upper end), and considering the average Pop III mass in dustyGadget galaxies at these redshifts in Equation (1). The oblique lines show the sensitivity of JWST/NIRSpec corresponding to an integrated S/N ∼ 3 line detection in both the IFU (left) and MOS (right) observing modes at z ≃ 6.7 and z ≃ 10 for different configurations, i.e., different resolving powers (R ∼ 1000/2700/100, with different thickness and markers), exposure times (∼10/50 hr; gray/golden), and line widths (500/50 km s−1; dashed–dotted). The corresponding lines for an integrated S/N ∼ 5 line detection with medium resolving power and a ∼ 50 hr exposure are also shown in red, with the same line styles as the S/N ∼ 3 case for the two assumed line widths.
Paper: A Hide-and-seek Game: Looking for Population III Stars during the Epoch of Reionization through the He II λ1640 Line
Authors: Alessandra Venditti, Volker Bromm, Steven L. Finkelstein, Antonello Calabrò, Lorenzo Napolitano, Luca Graziani, Raffaella Schneider
Figure caption: Top panels: number density of Pop III particles (n III) that we expect to find at a given redshift z in halos within a given range of stellar mass M ⋆ as a function of M ⋆, computed in six bins of M ⋆ (with a spacing of 0.5 dex in the range ﹩7.5\leqslant \mathrm{Log}{M}_{\star }/{M}_{\odot }\lt 10.5﹩). The total n III is shown as a gray solid line, while the n III found considering a single pointing of JWST/NIRSpec centered on the host galaxy in the IFU/MOS mode, respectively, are shown as golden/brown lines. The solid/dashed line style refer to the best/worst-case scenario for the orientation for the instrument, considering the worst line of sight to the source and an average line of sight (the latter are shown with thick transparent lines; see text and Figure 3 for details). The total number of Pop III particles found in each bin is also indicated on top of the bins. Bottom panels: fraction of Pop IIIs missed in JWST/NIRSpec pointings, with same color/line style convention. Results are shown for the combined simulated volumes U6, U7, U8, U10, U12, and U13 at redshifts z = 8.1 (left panels), z = 7.3 (middle panels), and z = 6.7 (right panels). We find that a significant number of Pop III systems can be overlooked in these configurations, especially in high-mass galaxies, although this problem appears to be less severe with NIRSpec/IFU thanks to its larger FOV.
Paper: A Hide-and-seek Game: Looking for Population III Stars during the Epoch of Reionization through the He II λ1640 Line
Authors: Alessandra Venditti, Volker Bromm, Steven L. Finkelstein, Antonello Calabrò, Lorenzo Napolitano, Luca Graziani, Raffaella Schneider
Figure caption: Illustration of a single JWST/NIRSpec pointing centered on Pop III-hosting galaxies (blue clouds) in the IFU/MOS modes, respectively (left/right; in the MOS mode, three consecutive shutters are considered). The distances d proj of the peripheral Pop III clusters (small blue clouds and red stars) from the galactic center in the displayed projection are shown as blue arrows, while the largest distances such that the clusters would certainly fall within the FOV independent of the instrument’s orientation (d min), or that conversely they would fall within for at least one possible orientation (d max), are shown as dashed–solid arrows, spanning the whole dashed–solid circumferences. The dimensions of the NIRSpec/IFU FOV and of the three shutters of NIRSpec/MOS are also indicated in the figure (not to scale). Depending on the orientation of the galaxies with respect to our instruments, peripheral Pop III systems might fall out of the FOV and would thus be missed in observations.
Paper: A Hide-and-seek Game: Looking for Population III Stars during the Epoch of Reionization through the He II λ1640 Line
Authors: Alessandra Venditti, Volker Bromm, Steven L. Finkelstein, Antonello Calabrò, Lorenzo Napolitano, Luca Graziani, Raffaella Schneider
Figure caption: Time-averaged He II photon emissivity per unit stellar mass ε HeII as a function of the initial Pop III mass m, from D. Schaerer (2002). The black solid line refers to the model assuming no mass loss (no ML; see Table 4 of the original paper), while the black dotted line refers to the model assuming strong mass loss (strong ML; see their Table 5). The average emissivity ﹩{\overline{\varepsilon }}_{\mathrm{HeII}}﹩ of Pop III stellar populations for the two models with our assumed Salpeter-like IMF in the range [100, 500] M ⊙, i.e., the values adopted in Equation (2) for the present work, are indicated on top of the horizontal solid/dotted black lines; the value for a Salpeter-like IMF in the range [1, 1000] M ⊙ with no ML is also indicated on top of the horizontal solid gray line (see text for details). The red dashed–dotted line further shows the cases of 300 M ⊙, 500 M ⊙, and 1000 M ⊙ stars evolving on the ZAMS along the entire stellar lifetime as a reference (V. Bromm et al. 2001b), to exemplify how mass loss keeps stellar evolution closer to the ZAMS, enhancing the time-averaged photon emissivity (as in the black dotted line).