adsabs/AstroCLIMB huggingface dataset:
Paper: A Spectroscopic Survey of Lyα Emitters and Lyα Luminosity Function at Redshifts 3.7 and 4.8
Authors: Weiyang Liu, Linhua Jiang
Figure caption: Source detection rates in the 5 SXDS subfields (upper panel) and SDF and SDFn (lower panel) as a function of the narrowband magnitudes. Differences between the curves reflect different depths of the narrowband images.
Paper: A Spectroscopic Survey of Lyα Emitters and Lyα Luminosity Function at Redshifts 3.7 and 4.8
Authors: Weiyang Liu, Linhua Jiang
Figure caption: Same as Figure 3, but for all LAEs at z ∼ 3.7 with 600 lines mm−1 grating spectra.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: Scatter plots comparing the electron beam parameters in 24 flares measured by Warmuth & Mann (2016) to the XRS peak flux and the XRS FWHM (in each channel, XRS-A in blue, XRS-B in red). The Pearson r  p  (correlation) and Spearman r  s  (monotonicity) coefficients are indicated. As reported by those authors, the parameters are strongly correlated with the peak SXR flux. Additionally, there may be a weaker correlation between the low-energy cutoff, electron rate, and nonthermal power with the duration of the flare in SXRs. Theil–Sen linear fits in log–log space have been overplotted and their slopes labeled.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: Irradiance time series for uniform, laminar 100 Mm loops, heated by an electron beam of 1011 erg s−1 cm−2 with various low-energy cutoffs E  c  = [10, 25, 30, 40, 50] keV. The durations and intensities are strongly affected by the value of E  c , which affects the strength of evaporation.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: The evolution of Hα, Lyα, and He II 304 Å. The plots on the left show the evolution of the line profiles from a simulation with a peak heating rate of F = 1010.3 erg s−1 cm−2, going from blue to yellow in time at a 100 s cadence, while the plots on the right show the time series from five simulations with various heating rates.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: A scatter plot of peak flux and duration in each XRS channel for the set of 27 cold flares from Lysenko et al. (2018). The correlation coefficients are small, and the slopes are consistent with 0. The distributions of durations are also shown for each XRS channel. The average durations are about an order of magnitude shorter than for “hot” flares.
Paper: Searching for C II Emission from the First Sample of z ∼ 6 O I Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array
Authors: Yunjing Wu, Zheng Cai, Jianan Li, Kristian Finlator, Marcel Neeleman, J. Xavier Prochaska, Bjorn H. C. Emonts, Shiwu Zhang, Feige Wang, Jinyi Yang, Ran Wang, Xiaohui Fan, Dandan Xu, Emmet Golden-Marx, Laura C. Keating, Joseph F. Hennawi
Figure caption: Left: Cross-correlation function between O I absorbers and their host galaxies. Symbols represent r 0 and γ measured from the Technicolor Dawn simulation (Finlator et al. 2020) with ﹩\mathrm{log}({N}_{\mathrm{OI}})﹩ comparable to our ALMA sample. Error bars are based on assuming the number of simulated host galaxies having Poisson fluctuations. The solid line shows the relation between r 0 and γ based on one detected galaxy with SFR ≈ 7 M⊙ yr−1 and within 20.0 pkpc in one of six absorber fields (see Section 3.1.2 for more details). The dashed black line shows the results derived from a 99% confidence-level Poisson uncertainty (Gehrels 1986) of the observed galaxy. Right: The cumulative number of galaxies around strong O I absorbers at z ≈ 6. The solid line shows the number of galaxies as the function of SFR within impact parameters of 50 kpc from simulations (Finlator et al. 2020), while the blue line represents a best-fit linear relation. The red square represents the averaged number of galaxies in our six absorber fields, while the red triangle shows the lower limit according to the Poisson uncertainty at the 99% single-sided confidence level.
Paper: Searching for C II Emission from the First Sample of z ∼ 6 O I Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array
Authors: Yunjing Wu, Zheng Cai, Jianan Li, Kristian Finlator, Marcel Neeleman, J. Xavier Prochaska, Bjorn H. C. Emonts, Shiwu Zhang, Feige Wang, Jinyi Yang, Ran Wang, Xiaohui Fan, Dandan Xu, Emmet Golden-Marx, Laura C. Keating, Joseph F. Hennawi
Figure caption: The number function of 1.1 mm continuum sources. The black symbols represent the number of sources in our QSO fields. The red diamond shows the results in the field of QSO J2054-0005. Error bars are determined by assuming Poisson uncertainties. The blue star is the five-field-averaged result. The black line is the double power-law fitted results from González-López et al. (2020).
Paper: Searching for C II Emission from the First Sample of z ∼ 6 O I Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array
Authors: Yunjing Wu, Zheng Cai, Jianan Li, Kristian Finlator, Marcel Neeleman, J. Xavier Prochaska, Bjorn H. C. Emonts, Shiwu Zhang, Feige Wang, Jinyi Yang, Ran Wang, Xiaohui Fan, Dandan Xu, Emmet Golden-Marx, Laura C. Keating, Joseph F. Hennawi
Figure caption: [C II] observations at the redshifts of six O I absorbers with z = 5.978, 5.753, 6.144, 6.112, 6.064, and 6.238, respectively. Color bars represent the integrated [C II] flux. These moment-zero maps are integrated over the central ∼300 km s−1 at the O I absorber redshifts. Solid black lines are searching areas of [C II] candidates, while black dashed lines represent the regions with primary beam limits >20%. Outer red contours start at 3σ, with increasing by 1σ. Meanwhile, negative contours are dashed red lines and start at −2σ. The beam size of each moment-zero map is demonstrated in the bottom left corner.
Paper: Searching for C II Emission from the First Sample of z ∼ 6 O I Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array
Authors: Yunjing Wu, Zheng Cai, Jianan Li, Kristian Finlator, Marcel Neeleman, J. Xavier Prochaska, Bjorn H. C. Emonts, Shiwu Zhang, Feige Wang, Jinyi Yang, Ran Wang, Xiaohui Fan, Dandan Xu, Emmet Golden-Marx, Laura C. Keating, Joseph F. Hennawi
Figure caption: Continuum observations of five QSO fields at different frequencies. The 1σ  rms of these fields are 0.012, 0.009, 0.018, 0.016, and 0.014 mJy/beam, respectively (from left to right). Contours are drawn at [3, 4, 5] × σ. Dashed contours represent −2σ. Black dashed lines are marked as the boundary of the primary beam limit >20%. Beam sizes are plotted on the bottom left. Excluding five QSOs, we still detect nine continuum sources in these QSO fields. Detailed information is demonstrated in Table 3. Zoom-in figures are shown at the corner of each panel.
Paper: Extreme Red-wing Enhancements of UV Lines during the 2022 March 30 X1.3 Solar Flare
Authors: Yan Xu, Graham S. Kerr, Vanessa Polito, Nengyi Huang, Ju Jing, Haimin Wang
Figure caption: The evolution of the Mg II k:h ratio within the source of interest as a function of time. The image shows wavelength vs. time, where the decrease in the ratio closer to unity in the red wing occurs near t = 0 s. The blue wing has a somewhat higher ratio. This can also be seen in the cutouts at specific times. The initial flare brightening produces a similar effect, but does not penetrate as far into the red wing.
Paper: Extreme Red-wing Enhancements of UV Lines during the 2022 March 30 X1.3 Solar Flare
Authors: Yan Xu, Graham S. Kerr, Vanessa Polito, Nengyi Huang, Ju Jing, Haimin Wang
Figure caption: Same as Figure 2 but for the IRIS 1330 Å SJI passband. The distorted feature in the bottom of the image, extending from x = 510″–514″, is the result of dust on the detector, which appears bright here since the image is shown on a logarithmic scale.
Paper: Extreme Red-wing Enhancements of UV Lines during the 2022 March 30 X1.3 Solar Flare
Authors: Yan Xu, Graham S. Kerr, Vanessa Polito, Nengyi Huang, Ju Jing, Haimin Wang
Figure caption: Same as Figure 3, but during the initial brightening of the flare ribbon that passes over the source of interest. The dotted horizontal line indicates the location of the source of interest.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Analysis of selected magnetic field line connectivity near the precursor brightening P1. (a) Two groups of brightening pixels from P1a and P1b are selected over the GST/Hα+0.6 Å image (in light blue shades) at 17:24:18 UT together with their conjugate field line footpoints based on the extrapolation result from Run 1. They are color-coded by the magnetic polarity of the corresponding field line footpoints on the bottom boundary: positive in red, and negative in cyan. Panels (b)–(d) show the field lines that originate in the red points in panel (a) for all three NLFFF extrapolation runs (Runs 1, 3, and 2), which are colored by height. In each panel, the B  z  map for Run 1 on the bottom boundary is drawn in gray scales, and the PIL is indicated by the white contours. In panels (a) and (b), the two white lines S1 and S2 indicate the positions of two vertical slices that are displayed in Figures 9 and 10.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Similar analysis for the selected field lines corresponding to the precursor brightening P2, based on the GST/Hα+0.6 Å image at 17:42:19 UT and the extrapolation results from all three runs. The format is the same as in Figure 5.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Evolution of the convergence metrics for the three extrapolation runs: (a) the residual of the magnetic field, (b) the current-weighted metric CWsin, (c) the total magnetic energy E tot, and (d) the divergence-freeness parameter 〈∣f  i ∣〉. In practice, the metrics in (b)–(d) are calculated for different domains. The domains size for metrics calculation are 192″ × 192″ × 96″ (140 × 140 × 70 Mm3) for Run 1 and Run 2, and 62.″5 × 53.″75 × 37.″5 (46 × 39 × 27 Mm3) for Run 3. Another smaller domain with a size of 62.″5 × 118.″75 × 37.″5 (46 × 87 × 27 Mm3), the same as the FOV of Figures 5 and 6, is additionally applied for Run 1.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Bottom boundary layers of the B  z  component for (a) the embedded magnetogram, (b) the uniform HMI magnetogram, and (c) a zoomed-in portion of (a) as outlined by the orange box. Panel (d) shows one associated nonuniform grid structure on the bottom boundary for (c). The whole domain is divided into blocks with equal sides, as illustrated in (d) for the bottom boundary by the solid lines, and each block contains 8 × 8 × 8 cells. The side length of the cell for the innermost block is 0.″125 (91 km), corresponding to the side length 1″ (730 km) of the blocks that form the core region, as shown. It doubles three times to reach the cell size 1″ for the outermost region, which is the buffer region. The intermediate region lies between these regions.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Magnetic field lines from three extrapolation runs within a height range of [0″, 60″] ([0, 44 Mm]) overplotted on the coaligned AIA 131 Å image at 17:36 UT. Panels (a) and (b) show field lines from Run 1 and Run 2 rooted in the same set of uniformly distributed seed points in a FOV of 190″ × 190″ (139 × 139 Mm2), which is similar to Figure 1(a). Panel (c) shows field lines from Run 3 in a smaller FOV due to the limited computational domain of Run 3. The dashed white box indicates the FOV of Figure 7.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Comparison between the field line connectivity and AIA observations in different wavelengths. Panel (a) All selected field lines from Run 1 in Figures 5 and 6 are superimposed on the AIA 131 Å observation. Panel (b) Contours of flare ribbons colored by the elapsed time since 16:55 UT (see the color bar) are overplotted with the set of field lines over an AIA 1600 Å image. Panels (c)–(d) The footpoints with positive (red) and negative (cyan) magnetic polarity for the set of field lines are drawn over the corresponding AIA 1600 and 1700 Å images.
Paper: Coronal Magnetic Field Extrapolation and Topological Analysis of Fine-scale Structures during Solar Flare Precursors
Authors: Wen He, Ju Jing, Haimin Wang, Sushree S. Nayak, Avijeet Prasad
Figure caption: Precursor brightenings and associated observations. Panel (a) shows the GOES X-ray flux during the precursors. The two dashed lines mark the emission times for the two precursors that occurred at ∼17:25 UT and ∼17:43 UT. Panels (b)–(e): Structural evolution of the Hα brightenings P1a/P1b and P2a/P2b from the GST observations as identified by Wang et al. (2017) before the peak of the main flare (reproduced from Figure 1 in Wang et al. 2017). Panel (f): Corresponding image observed in the SDO/AIA 193 Å wavelength. Panel (g) shows the corresponding GST/NIRIS magnetogram of the B  z  component. The yellow contour marks the PIL.
Paper: Early Planet Formation in Embedded Disks (eDisk). XII. Accretion Streamers, Protoplanetary Disk, and Outflow in the Class I Source Oph IRS 63
Authors: Christian Flores, Nagayoshi Ohashi, John J. Tobin, Jes K. Jørgensen, Shigehisa Takakuwa, Zhi-Yun Li, Zhe-Yu Daniel Lin, Merel L. R. van 't Hoff, Adele L. Plunkett, Yoshihide Yamato, Jinshi Sai (Insa Choi), Patrick M. Koch, Hsi-Wei Yen, Yuri Aikawa, Yusuke Aso, Itziar de Gregorio-Monsalvo, Miyu Kido, Woojin Kwon, Jeong-Eun Lee, Chang Won Lee, Leslie W. Looney, Alejandro Santamaría-Miranda, Rajeeb Sharma, Travis J. Thieme, Jonathan P. Williams, Ilseung Han, Suchitra Narayanan, Shih-Ping Lai
Figure caption: Channel map of formaldehyde (H2CO) emission in Oph IRS 63. The lowest contour emission corresponds to 3σ or 3 mJy beam−1, with increments of 3σ at a time. The FOV of the map is 8″ × 8″.
Paper: Spectro-polarimetric Properties of Sunquake Sources in X1.5 Flare and Evidence for Electron and Proton Beam Impacts
Authors: Alexander G. Kosovichev, Viacheslav M. Sadykov, John T. Stefan
Figure caption: (a) Variation of the Stokes I, (b) line profiles at various time moments before, during, and after the impact, and (c) the corresponding temperature profiles in the low atmosphere, calculated in the radiative hydrodynamics (RADYN) model driven by a proton with the energy flux of 1011 erg cm −2  s−1, the power-law index γ = 3, and the low-energy cutoff of E  c  = 1 MeV; ((d)–(f)) the same as panels ((a)–(c)) for E  c  = 3 MeV (Sadykov et al. 2023). The dashed line shows the semiempirical model of a white-light flare, obtained by Kleint et al. (2016).
Paper: Spectro-polarimetric Properties of Sunquake Sources in X1.5 Flare and Evidence for Electron and Proton Beam Impacts
Authors: Alexander G. Kosovichev, Viacheslav M. Sadykov, John T. Stefan
Figure caption: Red curve shows the filtergram signal at Source 1a from the HMI Camera 2 (level 1 data) normalized to the corresponding preflare values observed at 13:30 UT. The blue curves show the hard X-ray signal observed by the KONUS/WIND instrument in the energy range of 19–81 keV (thin curve) and 81–332 keV (thick curve).
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: XSM observed spectra (points with error bars) modeled with two-temperature (panel (a)) and three-temperature (panel (b)) models (solid lines). Different colors represent the spectra at different times during the flare, as mentioned in the plot. The temperature labels in the plot indicate the best-fitted temperatures associated with the flaring plasma (see the text for details).
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: Evolution of the abundances (points with error bars) of Mg, Si, and S during the flare. The red and black points represent the abundances obtained from 2T and 3T analyses (see text for details). The horizontal black line represents the abundance of the nonflaring plasma. The horizontal dashed lines of different colors represent the reported coronal abundances by Feldman (1992; blue), Fludra & Schmelz (1999; purple), and Schmelz et al. (2012; orange) as compiled in the CHIANTI database. The magenta line represents the values reported by Del Zanna (2013). The green shaded region shows the range of reported photospheric abundance in the literature. The gray curve represents the flare light curve.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: The evolution of the temperature (upper) and EM (lower) during the flare as obtained from the spectral analysis of XSM data. The red points represent the parameters associated with the flaring plasma for a 2T analysis (see text). Whereas the gray horizontal line represents the parameters associated with the nonflaring background plasma. The blue and black points near the peak of the flare represent the parameters obtained from the 3T model. The gray curve represents the flare light curve.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: Left panel: XSM observed spectra (points with error bars) overplotted with the predicted spectra (solid lines) obtained from the AIA EM for preflare (14:13 UT) and flare peak (14:16 UT) time. Since the temperatures and EMs derived from XSM and AIA are slightly different, due to differences in their energy sensitivities, a small deviation between the observed and predicted spectra at higher energies is reasonable. Right panel: simulated spectra for the AR on 2021 February 25 using EM values from XSM at flare peak time.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: The SDO/AIA images observed in multiwavelength channels targeting the AR 12804 observed on 2021 February 25 at flare peak time (14:16 UT). The wavelengths of different channels are noted at the top of the respective panels. The black box on the 94 Å image shows the region of the flare loops, shown in more detail in the following figures.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: Left panel: the AR in the 131 Å wavelength of SDO/AIA, showing the bright loop structures. The black contour is overlaid for the emission measure at log T = 7.1 showing temperatures above 9 MK. Right panel: the temporal evolution of the average effective temperatures integrated over 3 minute intervals from the contour shown in the left panel.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: Left and middle panels: XRT negative images for the Be-thin and Be-med filters at the flare peak time. The black contour shows the region considered for the calculation of the averaged effective temperatures. Right panel: XRT effective temperature map at the flare peak time using coronal abundances.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: The effective temperature variation using Be-thin/Be-med filter ratios from XRT. The black and red color indicates the temperature values using coronal and photospheric abundances, respectively.
Paper: Multiwavelength Observations of a B-class Flare Using XSM, AIA, and XRT
Authors: Yamini K. Rao, B. Mondal, Giulio Del Zanna, N. P. S. Mithun, S. V. Vadawale, K. K. Reeves, Helen E. Mason, Anil Bhardwaj
Figure caption: Emission measure maps of the AR data at the flare peak time (averaged for a 3 minute interval, 14:14 to 14:17 UT).
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: The cooling behavior of a uniform 100 Mm loop heated by a strong electron beam. The top plots show the time evolution of the electron temperature (left) and electron density (right) at the loop apex. The bottom six plots show the evolution of synthetic irradiance of six spectral lines. The vertical lines on each plot mark the time at which the coronal temperature reaches the peak formation of each spectral line. Once the corona cools beyond the formation temperature for each ion, the ion recombines and the irradiance falls off rapidly. The corona catastrophically collapses after about 50 minutes, and the lines fade entirely after this point.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: The cooling behavior of a 100 Mm loop with an expanding cross section heated by a strong electron beam, with strong turbulent suppression of thermal conduction. Similar to Figure 1. Both thermal conduction and draining of the loop have been suppressed, so cooling proceeds only through radiation, which takes significantly longer than the previous cases.
Paper: Generation of Subion Scale Magnetic Holes from Electron Shear Flow Instabilities in Plasma Turbulence
Authors: Giuseppe Arrò, Francesco Pucci, Francesco Califano, Maria Elena Innocenti, Giovanni Lapenta
Figure caption: (a) Close-up of the electron velocity shear at ﹩t=350\,{{\rm{\Omega }}}_{e}^{-1}﹩, where shaded isocontours indicate δ B  z  (in units of B 0), black streamlines represent the in-plane electron fluid velocity ﹩{\boldsymbol{u}}{{\prime} }_{e}﹩ while the green square box highlights the region where the EVDF is calculated. (b) 3D isosurfaces of the EVDF, with the red arrow indicating the direction of the local magnetic field.
Paper: Understanding the Duration of Solar and Stellar Flares at Various Wavelengths
Authors: Jeffrey W. Reep, Vladimir S. Airapetian
Figure caption: Illustration of the phases of evolution of emission in a coronal loop. There are generally three phases: a heating phase, a radiative cooling phase, and catastrophic collapse. The example light curves show a cool line (blue), forming near the lower transition region or upper chromosphere, a coronal line (gold), forming in the corona and upper transition region, and thermal free–free emission (red), forming in the corona. The evolution depends strongly on the height at which emission forms.