adsabs/AstroCLIMB huggingface dataset:
Paper: Electron Density Distribution in H II Regions in IC 10
Authors: Fiorella L. Polles, Dario Fadda, William D. Vacca, Nicholas P. Abel, Mélanie Chevance, Christian Fischer, James M. Jackson, Vianney Lebouteiller, Suzanne Madden, Lise Ramambason
Figure caption: The dust continuum ratio 70 μm/100 μm vs. n e [O III] (top) and vs. n e [S III] (bottom). The color code and symbols are the same as Figure 3. Spearman's rank correlation coefficient is indicated in the top right corner (ρ).
Paper: Electron Density Distribution in H II Regions in IC 10
Authors: Fiorella L. Polles, Dario Fadda, William D. Vacca, Nicholas P. Abel, Mélanie Chevance, Christian Fischer, James M. Jackson, Vianney Lebouteiller, Suzanne Madden, Lise Ramambason
Figure caption: 24 μm luminosity vs. n e [O III] values (top) and observed Hα luminosity vs. n e [O III] values (bottom). Left: c1 subregions; middle: c2 subregions; right: c3 subregions. Spearman's rank correlation coefficient is indicated in the top right corner (ρ).
Paper: Electron Density Distribution in H II Regions in IC 10
Authors: Fiorella L. Polles, Dario Fadda, William D. Vacca, Nicholas P. Abel, Mélanie Chevance, Christian Fischer, James M. Jackson, Vianney Lebouteiller, Suzanne Madden, Lise Ramambason
Figure caption: Hα image of IC 10 with the positions of the WR stars from Tehrani et al. (2017) overlaid. The regions analyzed in this study are indicated with blue circles.
Paper: Electron Density Distribution in H II Regions in IC 10
Authors: Fiorella L. Polles, Dario Fadda, William D. Vacca, Nicholas P. Abel, Mélanie Chevance, Christian Fischer, James M. Jackson, Vianney Lebouteiller, Suzanne Madden, Lise Ramambason
Figure caption:  n e [O III]/n e [S III] ratio vs. n e [O III] values for different integrating areas (from left to right, c1, c2, and c3). The color code and symbols are the same as Figure 3.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Dynamic spectra for WASP-69 b show the eclipse as a horizontal dark band. The eclipse depth (as seen by the darkness of the band) increases from short wavelengths toward long wavelengths, and also shows a dip where there is strong CO2 atmospheric absorption near 4.3 μm. The dynamic spectra are the extracted spectra for each detector column (NIRCam) and row (MIRI) at full spectral and full time resolution without binning. The top panels of each dynamic spectrum show the average spectrum in electrons for one integration.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Left: eclipse spectrum with three independent extraction and lightcurve fitting methods on a common ∼0.010 μm-spaced grid. All spectra agree within the ∼50–80 ppm error bars. Right: eclipse spectrum with MIRI with two independent extraction and lightcurve fitting methods.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Top half-panels: broadband eclipse lightcurves with a best-fit model. Bottom half-panels: residuals of the model.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: The emission spectrum of WASP-69 b shows significant absorption features from molecules in its atmosphere and a trend from high to low brightness temperature from 2.1 to 12 μm. Top: binned emission spectrum of WASP-69 b in terms of planet-to-star flux for the NIRCam and MIRI data, colored by their respective filters. The full higher-resolution NIRCam data (which are used for atmospheric retrieval) are shown as points and the binned spectra are shown for illustrative purposes as lines with error bars. The MIRI full resolution is the same as the binned one due to its intrinsically lower resolution. Synthetic photometry calculated for the IRAC 3.6 and 4.5 channels (gray circles) indicates larger eclipse depths than Spitzer-published measurements (purple points with error bars; Wallack et al. 2019). Blackbody planetary spectra for example temperatures are shown as black lines. Middle: the spectrum is poorly fit by a clear 1D homogeneous model (dashed blue line), where it overpredicts the flux at MIRI wavelengths (5–12 μm), overpredicts the 3.9  μm flux, and underpredicts the shortest wavelengths (2.5–3.2 μm). It is necessary to include the effects of clouds (thin orange line) as well as dayside inhomogeneities (thick green line) to fit the spectrum of the planet. Bottom: the brightness temperature spectrum shows absorption signatures of H2O, CO2, and CO. The relative pressure level where each molecule has an optical depth of 1 is shown for each model in the style of Mukherjee et al. (2024). We plot two models, described in Section 5, which can alternatively fit the spectrum of WASP-69 b with either significant reflection (scattering model) or a high-altitude cloud (cloud-layer model).(The data used to create this figure are available in the online article.)(The data used to create this figure are available.)
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Left: the two-region model can fit the spectrum with a hot temperature–pressure profile that covers 68% of the dayside area and a cooler, cloudier region that contributes negligibly to the planet flux. The binned data are shown as gray diamonds with error bars. The individual spectra from the hot component (gray dotted line) and cold component (gray dashed line) are combined via Equation (1) to give a best-fit spectrum (thick cyan line). A model with no reflected light and only thermal flux (thin red line) and the hot component’s emission only (dotted orange line) show that reflected light and the cold component’s emission are both negligible compared to the thermal emission from the planet’s hot region. This also means that the dilution parameter used in the cloudy layer and scattering models should give very similar results as two separate regions. Right: our measured spectrum shows signatures of H2O, CO2, and CO molecules as well as clouds to both suppress the emission from the cold region and the 4 μm and 9–11 μm emission from the hot region. We remove one molecule at a time and plot the change in spectrum as a shaded region spanning from the best-fit model (cyan line) to the molecule-removed and cloud-removed spectra (color-shaded regions). The binned data (gray diamonds) are the same as on the left plot. We note that removing H2O can decrease the flux as compared to the best-fit model because it increases the single-scattering albedo and thus decreases the emissivity of the photosphere.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Temperature–pressure profile (upper left) and cloud properties for the silicate cloud model. The TP profile for the cloud-layer model crosses the condensation curve for Na2S (dashed gray line) at very high altitudes and MgSiO3 (dashed pink line) at very deep altitudes, while the scattering model crosses neither of these cloud candidates’ condensation curves. While the cloud layer crosses these two condensation curves, Na2S has inefficient nucleation rates from theoretical models (Gao & Benneke 2018) and MgSiO3 would require extreme verticle mixing to be lofted to the high altitudes needed to match the observed brightness spectrum. The upper-right three panels show the optical properties of the retrieved silicate clouds: optical depth τ cld, asymmetry g 0, and single-scattering albedo w 0, at a reference wavelength of 10 μm.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Posterior densities of retrieved atmospheric parameters from PICASO for the scattering model (red) and the cloud-layer model (blue). The modeled parameters (from left to right and down) are the atmospheric log metallicity relative to solar composition ([M/H]), the absolute carbon-to-oxygen ratio (C/O), the geometric albedo (A g, scattering model only), the dayside area dilution (s dilute), five temperature–pressure profile parameters from Line et al. (2013): the T eq parameter (not consistent with the planet’s equilibrium temperature, described in the text), log(g), κ IR, the internal heat flux temperature T int,α, and finally a free-floating SO s  abundance (SO2). Stair-step 2D representations of these posteriors can be found in Figures 16 and 17.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Top: calibrated absolute flux for three observations of the host star WASP-69 A and a 4750 K BOSZ model (Bohlin et al. 2017). Additionally, photometry from 2MASS K  S  and WISE bands 1–3 is shown as data points with error bars. The black circles are synthetic photometry of the BOSZ model for those same photometric bands. Bottom: the ratio of the data over the model shows closest agreement in the F322W2 filter (where a direct ratio with a calibrator was possible) and some 1%–3% discrepancies where stellar CO absorption is present. No circumstellar debris disks are present above ≳3% flux levels that could dilute the planet’s flux significantly.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Contribution functions for the two-region model (top row) and the cloud-layer model (bottom plot). The individual regions' contributions are shown for the two-region model (top-left two plots) as well as the combined full dayside (right plot). A high-altitude (10−4–10−5 bar) cloud dominates the longer-wavelength emission (with smaller brightness temperatures) while the warmer lower layers dominate at short wavelengths (with larger brightness temperatures) in both models. The posterior retrieved temperature–pressure profile for the CHIMERA model (bottom middle) is shown as a red curve with the temperature at the top axis.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Posterior maps for the nonuniform map fits to WASP-69 b’s dayside. The maps only include the Y 2,0 and Y 1,0 spherical harmonics to sense temperature gradients, but do not reveal location information. The mean map (left) and error (right) favor a dayside brightness distribution that is centrally concentrated and inefficient at redistributing heat. The plus sign shows the peak brightness, which is forced to be at the substellar point by the limited number of spherical harmonics.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Retrieved posterior distribution for the two-region model. The physical constraints of the model give tight bounds on the metallicity and C/O ratio of the planet. The hotter region fills about 68% of the dayside in this retrieval.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: MIRI LRS broadband lightcurves and residuals for lightcurve fits to the uniform map as well as the model difference between the nonuniform map and the uniform map. The nonuniform map allows for a gradient from the substellar point to the terminator through the Y 2,0 and Y 1,0 spherical harmonics. The Bayesian information criterion (BIC) favors the nonuniform map (BIC = 184.1 vs. BIC = 191.1), but higher signal-to-noise is needed to robustly map WASP-69 b to high confidence.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: The dayside temperature from our JWST spectrum indicates that heat is not fully recirculated around the planet. The allowed ranges of dayside temperature from full redistribution of heat around the planet (solid line) to zero redistribution of heat (dotted line) for a given Bond albedo are bounded within the gray region. The integrated thermal flux from the planet extrapolated to 0  μm and ∞ μm is calculated for our better-fitting models (thick red line, orange line, and thin blue line). The high geometric albedo of the scattering model (blue) which pushes against the prior of 0.67 strongly indicates a high Bond albedo, so we show values below 0.4 with a dashed line. The scattering model barely conserves energy at the highest geometric albedo and would result in a very extreme dayside-to-nightside temperature contrast.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: The abundance of WASP-69 b is constrained largely by the H2O feature at 2.8 μm, the lack of a CH4 feature at 3.3 μm, the CO2 feature at 4.3  μm, and the CO feature at 4.5 to 5.0 μm. Upper left: three forward models are shown for three different atmospheric enrichments of [M/H] = 1.5, [M/H] = 1.01 (the best-fit value), and [M/H]. In these three examples, the relative abundances of heavy elements, including the C/O ratio, is held constant. Lower left: the residuals of the models at three different atmospheric enrichments shows the most significant offsets are due to H2O near 2.8  μm and CO2 at 4.3 μm. Upper right: three forward models are shown for three different C/O ratios of 1.0, 0.79 (best-fit value), and 0.3. These three models preserve the overall abundance of heavy elements. At high C/O ratios, CH4 is expected to be a significant absorber and causes a pronounced 3.3  μm feature, not observed in WASP-69 b. Lower right: high C/O ratios are ruled out because there is no strong 3.3  μm CH4 feature, and low C/O ratios are disfavored because they have large abundances of H2O and make a deeper 2.8  μm feature as well as shrink the size of the 4.3  μm CO2 absorption trough.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Two-dimensional posterior distributions of the cloud-layer model (bullet item 5, Sections 5.2.3 and 5.3.3). The parameters are temperature–pressure profile parameters: T eq (not necessarily consistent with planet’s equilibrium temperature), T int, log(g), κ IR and α, the carbon-to-oxygen ratio C/O, the atmospheric metallicity [M/H], the free SO2 abundance SO2, the area fraction of the model emission compared to the full planet disk s dilute, and the cloud parameterization parameters: the logarithm of the geometric mean radius log(rad), the geometric standard deviation of radius σ, the logarithm of the cloud base pressure in bars log(cld_pres), the log of the sedimentation efficiency log(f sed), and the normalization factor ndz.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: The detector housing temperature is anticorrelated with flux across many different NIRCam observations, so we use it as a means to detrend the data. Here, the X-axis shows the change in the wavelength-integrated flux from the median in parts per million for all out-of-transit and out-of-eclipse integrations for six different example observations in the MANATEE program number 1185. The Y-axis shows the change in focal plane array housing (FPAH) as measured by the telemetry keyword IGDP_NRC_A_T_LWFPAH1. Each observation is listed with the program number, observation number, and which long-wavelength filter was used, respectively. The observations describe in this paper are 006 and 007, as listed in Table 1.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Two-dimensional posterior distributions of the scattering model (bullet item 4, Sections 5.2.2 and 5.3.2) . The parameters are temperature–pressure profile parameters: T eq (not necessarily consistent with planet’s equilibrium temperature), T int, log(g), κ IR and α, the carbon-to-oxygen ratio C/O, the atmospheric metallicity [M/H], the free SO2 abundance SO2, the constant geometric albedo A g, and the area fraction of the model emission compared to the full planet disk s dilute.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Left: experiment as to whether enhanced or decreased H2S could help fit the data better without requiring a temperature gradient on the dayside. We show the single-region model with equilibrium H2S for reference (black) as well as highly enhanced and highly diluted abundances of H2S, neither of which can significantly improve the model as compared to the data. Right: using the same single-region forward model, we also vary the SO2 abundance to explore another sulfur-bearing molecule. While extra SO2 can help fit the data from 7.3 to 7.7 μm, it cannot raise the 2.8  μm flux and lower the 6–9  μm flux to match the data as well as the two-region model.
Paper: Multiple Clues for Dayside Aerosols and Temperature Gradients in WASP-69 b from a Panchromatic JWST Emission Spectrum
Authors: Everett Schlawin, Sagnick Mukherjee, Kazumasa Ohno, Taylor J. Bell, Thomas G. Beatty, Thomas P. Greene, Michael Line, Ryan C. Challener, Vivien Parmentier, Jonathan J. Fortney, Emily Rauscher, Lindsey Wiser, Luis Welbanks, Matthew Murphy, Isaac Edelman, Natasha Batalha, Sarah E. Moran, Nishil Mehta, Marcia Rieke
Figure caption: Extraction aperture. The inner and outer circles are the background annulus radii and the source aperture is the same as the inner background annulus radius.