adsabs/AstroCLIMB huggingface dataset:
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Stellar-contamination-corrected combined spectrum of LHS 1140 b using the best-fit solution of Figure 2. The black points are binned to R ∼ 20, while the gray points are at a higher R ∼ 100. Dashed lines depict GCM-based forward models produced with PSG for a mini-Neptune atmosphere (100×, 300×, 1000× solar metallicity), and solid lines depict the water-world GCMs of Cadieux et al. (2024) for an Earth-like atmosphere (1 bar N2, 400 ppm CO2) and a pure CO2 atmosphere at 5 bars. An H2-rich atmosphere for LHS 1140 b is formally rejected (>10σ) by the NIRISS/SOSS data. A flat solution (e.g., water world or airless planet) provides a significantly better fit, but the reduced χ 2 of 1.75 may indicate an underestimation of error bars, an imperfect TLS correction, or the presence of residual spectral features (e.g., slope). An apparent linear trend with a slope of approximately 40 ppm across the NIRISS domain (dotted green line) improves the fit (﹩{\chi }_{\nu }^{2}=1.72﹩) but is not predicted by our GCMs.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Escape velocity–instellation diagram of small exoplanets (R  p  < 1.8 R ⊕). The empirical “cosmic shoreline” (﹩S\propto {v}_{\mathrm{esc}}^{4}﹩) of Zahnle & Catling (2017) based on solar system bodies is depicted in orange with an arbitrary envelope to underscore uncertainty with spectral types. The size of data points scales with their Transmission and Emission Spectroscopy Metrics (TSM and ESM; Kempton et al. 2018) to highlight favorable targets for JWST atmospheric characterization. Targets with S < 10 S ⊕ or with TSM/ESM above 90th percentile are annotated. The TRAPPIST-1 system is abbreviated as “T-1.” The optimistic habitable zone (early Mars/recent Venus) defined by Kopparapu et al. (2013) is shown in green (approximated for a range of spectral types). With a relatively high escape velocity and low instellation, LHS 1140 b likely retained an atmosphere.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Predicted emission spectrum of LHS 1140 b for various scenarios, including the Earth-like (1 bar N2, 400 ppm CO2) and pure CO2 (5 bars) atmosphere cases from the GCMs of Cadieux et al. (2024). Extreme Bond albedo cases (0 or Europa-like) with no atmospheric heat redistribution (f = 2/3) are shown with dashed lines. The gray envelope represents the 10% uncertainty of LHS 1140's stellar flux inferred from a BT-COND model. The red plus sign, centered on the deepest airless case (A B = 0, f = 2/3), gives the predicted uncertainty at 15 μm for three visits needed to reach a 3σ detection assuming photon-limited performance. Similarly, the green plus sign gives the number of visits needed (7) for detecting the deepest eclipse at 21 μm. Each visit is assumed to last ∼7.5 hr (1 hr + 3 times the transit duration), a similar experimental design to that adopted by Greene et al. (2023) and Zieba et al. (2023) for the MIRI observations of TRAPPIST-1 b and c, respectively.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Spectrophotometric transit fits of LHS 1140 b for visit 1 (UT2023-12-01; left) and visit 2 (UT2023-12-26; right) and LHS 1140 c for visit 2 only. The broadband (“white”) light curves are shown in the top panels, with the best-fit full model (transit + systematics) shown in black and systematics component only in pink (scaled 10×  for clarity). For both visits, examples of 10 systematics-corrected spectroscopic bins are depicted with colored points in the bottom panels.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Combined (two visits) transmission spectrum of LHS 1140 b on the left and (one visit) transmission spectrum of LHS 1140 c on the right extracted with the SOSSISSE and supreme-SPOON pipelines, here shown for the first order of NIRISS/SOSS. The transit light-curve fitting is identical between pipelines; any differences arise during the reduction stages. The panels below show the difference in transit depths (SOSSISSE − supreme-SPOON) normalized by the maximum errors between the two pipelines at each spectral bin. A running mean (window = 5) is drawn with a blue curve showing no clear trends in the residuals. The pipelines are in good agreement with an average per-point difference of 0.72σ and 0.58σ for the spectra of LHS 1140 b and c, respectively.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Tentative evidence of a N2-dominated atmosphere on LHS 1140 b. The stellar-contamination-corrected LHS 1140 b NIRISS/SOSS transmission spectrum (black points for R ∼ 20, gray points for R ∼ 100) is compared with the best-fitting model transmission spectra for a 100% N2 atmosphere (green) and a 100% CO2 atmosphere (blue), plotted at R = 20. The N2 model has a best-fitting T = 399 K, while the CO2 model has T = 116 K. The N2 model provides a better fit (2.3σ), due to the presence of a Rayleigh scattering slope and a weak N2–N2 CIA feature.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Results of GCM simulations of LHS 1140 b assuming mini-Neptune thick H2 atmosphere (100×, 300×, and 1000× solar metallicity composition), an Earth-like atmosphere (1 bar N2, 400 ppm CO2), and a thick CO2-dominated atmosphere (5 bar of CO2). Panels show vertical profiles of the atmospheric temperatures (left), water vapor mixing ratio (middle), and water cloud mixing ratios (right). The thick solid lines indicate the global mean vertical profiles, and the dotted lines indicate the terminator vertical profiles (impacting transit spectra).
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Transmission spectrum of LHS 1140 c from NIRISS/SOSS at an R ∼ 20 (white points) and at a higher R ∼ 100 (gray points). The best-fit models from POSEIDON with 1σ–2σ confidence envelopes are shown for a stellar contamination model (orange) and a joint stellar contamination and planetary atmosphere model (blue). The TESS and Spitzer photometric measurements (Cadieux et al. 2024) are shown in red. We have included the Spitzer point in the retrieval analysis, but its exclusion does not change the results. The NIRISS/SOSS observations are flat, with marginal evidence of unocculted faculae consistent with the simultaneous transit of LHS 1140 b (Figure 2). The spectrum covering 0.65–2.7 μm has an average transit depth that falls between those measured by TESS and Spitzer, resolving the 4σ discrepancy in radius measurements between the two instruments noted by Cadieux et al. (2024).
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Posterior distribution for the joint N2 atmosphere and stellar contamination retrieval of LHS 1140 b’s combined NIRISS/SOSS transmission spectrum. Note that N2 does not show in the corner plot as a free parameter because the N2 abundance is fixed to 100% for this model.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Posterior distribution for the joint multigas atmosphere with hazes, a cloud/surface, and stellar contamination retrieval of LHS 1140 b’s combined NIRISS/SOSS transmission spectrum.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Posterior distribution for the joint multigas atmosphere with hazes and stellar contamination retrieval of LHS 1140 b’s combined NIRISS/SOSS transmission spectrum.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Posterior distribution for the stellar-contamination-only (“TLS-only”) POSEIDON retrieval of LHS 1140 b’s combined NIRISS/SOSS transmission spectrum.
Paper: Transmission Spectroscopy of the Habitable Zone Exoplanet LHS 1140 b with JWST/NIRISS
Authors: Charles Cadieux, René Doyon, Ryan J. MacDonald, Martin Turbet, Étienne Artigau, Olivia Lim, Michael Radica, Thomas J. Fauchez, Salma Salhi, Lisa Dang, Loïc Albert, Louis-Philippe Coulombe, Nicolas B. Cowan, David Lafrenière, Alexandrine L'Heureux, Caroline Piaulet-Ghorayeb, Björn Benneke, Ryan Cloutier, Benjamin Charnay, Neil J. Cook, Marylou Fournier-Tondreau, Mykhaylo Plotnykov, Diana Valencia
Figure caption: Posterior distribution for the joint multigas atmosphere with hazes and stellar contamination of LHS 1140 c’s NIRISS/SOSS transmission spectrum.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: Breakout condition in terms of the jet efficiency ﹩{L}_{{\rm{j}}}/\dot{M}{c}^{2}﹩ and misaligned angle θ LS for the parameter values of θ 0 = 0.33, f w = 0.5, β w = 0.1. The gray solid line shows the jet breakout criterion. The darker regions indicate a breakout jet, whereas the lighter regions indicate a choked jet. The yellow regions, the red regions, and the gray region represent collimated jets with a nonrelativistic jet head, collimated jets with a relativistic jet head and uncollimated jets, respectively. The horizontal black solid line shows the case of Swift J1644+57 with a jet efficiency of η = 0.023. Note that we simply use the region larger than unity to denote the figure labels.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: Color map of the expected neutrino numbers for three TDEs (AT2019dsg, AT2019fdr, and AT2019aalc) as a function of the jet efficiency η and initial opening angle θ 0 with a fixed misaligned angle θ LS = π/4. The white dashed line represents the minimal required neutrino numbers inferred from observations. The black vertical line represents the maximum jet efficiency limited by the breakout criterion, while the white solid line represents the critical jet efficiency η  c  = 0.0025.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: Color map of the expected neutrino numbers for three TDEs (AT2019dsg, AT2019fdr, and AT2019aalc) as a function of the jet efficiency η and misaligned angle θ LS with an initial jet half-opening angle of θ 0 = 0.33 and Γ = 10. The meanings of each of the lines are the same as in Figure 5.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: Breakout condition in terms of the dimensionless term ﹩{L}_{{\rm{j}},\mathrm{iso}}/{\beta }_{{\rm{w}}}{\dot{M}}_{{\rm{w}}}{c}^{2}﹩ and misaligned angle θ LS using the same parameters as those in Figure 2. The solid gray line represents the breakout criterion when the collimation caused by the cocoon pressure is taken into account, while the blue dotted–dashed line shows the breakout condition without taking into account the collimation effect (i.e., assuming that jets are conical). The meanings of the regions with different colors are the same as in Figure 2.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: The evolution of θ j adopting Equation (7). Top: θ j/θ 0 as a function of ﹩\tilde{L}﹩ for various initial jet opening angles θ 0. Bottom: θ j/θ 0 as a function of the jet efficiency η for various initial jet opening angles θ 0.
Paper: Choked Precessing Jets in Tidal Disruption Events and High-energy Neutrinos
Authors: Qi-Rui Yang, Jian-He Zheng, Ruo-Yu Liu, Xiang-Yu Wang
Figure caption: Color map of neutrino numbers as the function of misaligned angle vs. jet power in a general case. The solid black line represents the breakout condition, and the dotted–dashed black line corresponds to a jet similar to Swift J1644 with a jet luminosity of 1046 erg s−1. The left side of the black solid line corresponds to the region where jets will not break through the envelope, and vice versa.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Total dust mass vs. disk size for Class 0/I disks in the Orion star-forming region with both ALMA (0.87 mm) and VLA (9 mm) measurements, denoted with gray circles. Vertical dotted lines delineate the boundaries of the eight logarithmically spaced radial bins from the minimum to maximum disk sizes. Median M dust for each bin is at the center of the orange crosshair with the lower and upper tips of the crosshair indicating the 16th and 84th percentiles, respectively. The least-squares fit accounting for the spread in M dust in each bin (taken as the quadrature sum of the lower and upper spread) are shown as a blue line with the result of the fit annotated at the top in blue text. Only the outer six radius bins are included in the fit, as the inner two bins contain less than three points.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Estimated local gas surface density Σ g  for the derived minimum St for gravitational stability (St Q  in Table 2; filled circles) and the maximum St to be consistent with the ring dust mass (St M  in Table 2; open circles) for each ring. Where available, we indicate with blue squares the estimated Σ g  from Powell et al. (2019; AS 209 B74 and B120, HD 163296 B67 and B100) and with magenta squares the measured Σ g  from Booth et al. (2019; HD 163296 B67 and B100), where for the latter, we take the values in Table 2 of Rosotti et al. (2020).
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Contour map of St (top row) and α (bottom row) as a function of St/α and the ring mass for a system parameter following Elias 24 B77 (see Table 1) with median M dust (see Figure 1). Whether we assume constant St (left column) or constant grain size (right column) makes negligible difference in the calculated St and α. The purple dashed lines in the top row draw the St that corresponds to Toomre Q = 1 such that larger St would be consistent with local gravitational stability (see Section 2.4). The purple dashed line in the bottom row delineates α = 10−4, below which the disk is in the strongly inviscid limit. The measured St/α and M ring for Elias 24 B77 are indicated with black circles with the upper and lower limits connected by a line.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Mass growth of a dust clump within AS 209 B120 (pink line). Shown in other lines are the rescaled mass growth if the ring were to be placed at closer-in distances with the same M ring, w  d /a ring, St, and α. Planet formation is prohibitively slow at the measured location of the ring but accelerates dramatically inside 10 au, potentially engulfing all the ring masses if placed at 3 au.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Derived St as a function of initial disk dust mass percentiles. For each system, the minimum St required for local gravitational stability is drawn by a horizontal dashed line.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Derived St (top row) and α (bottom row) for individual rings from Table 1. Filled circles represent minimum St for local gravitational stability and corresponding α, whereas unfilled circles represent the maximum St that satisfies the disk mass budget and its corresponding α. In general, all the rings indicate low St ≲ 10−2 and low α ≲ 10−3, consistent with being approximately inviscid.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: Estimated local dust-to-gas mass ratio for minimum St (filled circles) and maximum St (unfilled circles) for each ring. Plotted in red circles are the critical dust-to-gas mass ratio for triggering SI, taking into account extra gas turbulence (e.g., an unknown source generating the dust trap) in addition to what would be generated from dust–gas interaction. All rings studied are expected to be stable against clumping by SI.
Paper: Probing Dust and Gas Properties Using Ringed Disks
Authors: Eve J. Lee
Figure caption: The ratio of the ring surface density (Equation (15)) to the minimum density required for nucleation of the bound clump (Equation (16)) vs. the radial location for each ring. The plotting scheme is identical to that of Figure 3. None of the rings are able to nucleate stable clumps.
Paper: Direct Observational Evidence of Multi-epoch Massive Star Formation in G24.47+0.49
Authors: Anindya Saha, Anandmayee Tej, Hong-Li Liu, Tie Liu, Guido Garay, Paul F. Goldsmith, Chang Won Lee, Jinhua He, Mika Juvela, Leonardo Bronfman, Tapas Baug, Enrique Vázquez-Semadeni, Patricio Sanhueza, Shanghuo Li, James O. Chibueze, N. K. Bhadari, Lokesh K. Dewangan, Swagat Ranjan Das, Feng-Wei Xu, Namitha Issac, Jihye Hwang, L. Viktor Tóth
Figure caption: (a) The color–magnitude diagram of the sources associated with G24.47 within the circle shown in (c). The ZAMS loci, with the spectral types indicated, are drawn for 0, 10, 20, and 30 magnitudes of visual extinction corrected for the distance. The parallel lines are the reddening vectors for the spectral types. Stars earlier than spectral type B3 are shown as stars. (b) The color–color diagram for the 23 sources earlier than B3. The loci of giants and main-sequence stars, taken from Koornneef (1983) and Bessell & Brett (1988), are shown as black and green curves, respectively. The dashed line shows the locus of the Herbig AeBe stars adopted from Lada & Adams (1992). The locus of classical T Tauri (Meyer et al. 1997) is shown as a dashed–dotted line. The parallel lines are the reddening vectors where the ones corresponding to M4, B3, and O5 are shown as dotted lines. The cross marks indicate intervals of 5 mag of visual extinction. Sources (E1–E12) within the reddening vectors of B3 and O5 are labeled in panels (a) and (b). Both plots are in the Bessell & Brett (1988) system. (c) The color scale shows the VLA 4.86 GHz map of the region associated with G24.47 with contour levels at [3, 7, 20, 35, 50, 70, 90, 100, 110, 120, 135] × σ (σ = 0.4 mJy beam−1). The crosses represent the central positions of the VLA cores. The positions of the sources E1–E12 are indicated. The ellipse at the bottom left shows the beam.