adsabs/AstroCLIMB huggingface dataset:
Paper: Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni
Authors: Jia-Shu Niu, 家树 牛, Yue Liu, 越 刘, Hui-Fang Xue, 会芳 薛
Figure caption: Correlation chart based on F1 (amplitude) and F11 (frequency), Part I.
Paper: Uncorrelated Amplitude and Frequency Variations of the Harmonics in SX Phoenicis Star XX Cygni
Authors: Jia-Shu Niu, 家树 牛, Yue Liu, 越 刘, Hui-Fang Xue, 会芳 薛
Figure caption: Correlation chart based on F1 (amplitude) and F11 (frequency), Part II.
Paper: Radio-optical Reference Catalog, Version 1
Authors: Valeri V. Makarov, Megan C. Johnson, Nathan J. Secrest
Figure caption: Graphical presentation of the VSH-fitted Gaia−Ka position offsets on the celestial sphere in the Aitoff equatorial projection. Orange dots at the origin of vectors indicate the actual position of Ka sources. The length and direction of small vectors represent the cumulative VSH fit for the corresponding point. The median length of the arrows is 324  μas. The gray line shows the location of the nominal Galactic equator.
Paper: Radio-optical Reference Catalog, Version 1
Authors: Valeri V. Makarov, Megan C. Johnson, Nathan J. Secrest
Figure caption: Configuration plots for two sources showing the derived RORC-1 position at the center and its error ellipse (blue-thick line) and the VSH-corrected positions with their error ellipses from the available input catalogs Gaia, S/X, K, and Ka, as indicated in the legend.
Paper: Radio-optical Reference Catalog, Version 1
Authors: Valeri V. Makarov, Megan C. Johnson, Nathan J. Secrest
Figure caption: Singular values of the VSH fits for the three radio-optical cleaned samples (S/X, K, and Ka) normalized to the greatest singular value s 1.
Paper: The Panchromatic Hubble Andromeda Treasury. XX. The Disk of M31 is Thick
Authors: Julianne J. Dalcanton, Eric F. Bell, Yumi Choi, Andrew E. Dolphin, Morgan Fouesneau, Léo Girardi, David W. Hogg, Anil C. Seth, Benjamin F. Williams
Figure caption: Comparison between the structure of M31's RGB disk and the structure of the Milky Way’s monoabundance populations from Bovy et al. (2012a). (Left) Monoabundance populations in [Fe/H] vs. [α/Fe], color coded by their vertical scale height at the solar circle. Populations whose scale height falls in the range allowed by the data in M31 are outlined in black. Only low-metallicity, α-enhanced Milky Way populations have scale heights comparable to those we see in M31. (Right) The axial ratio of the monoabundance subpopulations as a function of [Fe/H] calculated as a mass-weighted average of h  z /h  r  over [α/Fe] at fixed [Fe/H]. Points are color coded by the fraction of the integrated local stellar density found in populations with metallicities equal to or lower than [Fe/H]. The horizontal bar show the likely range of h  z /h  r  for M31's stellar disk. Only low-metallicity populations ([Fe/H]≲ − 0.5) that make up ∼30% of the Milky Way disk are as puffy as the M31 disk.
Paper: The Panchromatic Hubble Andromeda Treasury. XX. The Disk of M31 is Thick
Authors: Julianne J. Dalcanton, Eric F. Bell, Yumi Choi, Andrew E. Dolphin, Morgan Fouesneau, Léo Girardi, David W. Hogg, Anil C. Seth, Benjamin F. Williams
Figure caption: Comparison between the structure of M31's RGB disk and the structure of edge-on disks from observations in the NIR. Circular points are disk axial ratios (h  z /h  r ) as a function of the galaxy circular velocity, color coded by scale height for the single-disk fits from Yoachim & Dalcanton (2006), based on fitting 2D models to K  s  imaging data for bulgeless galaxies selected from Karachentsev et al. (1993)'s Flat Galaxy Catalog; points with heavy black outlines have values of h  z  within range of the values compatible with our results for M31. The red rectangular region indicates the range of h  z /h  r  found for 2D fits of either 2MASS or Spitzer imaging of edge-on galaxies with bulge-to-total ratios greater than zero by Mosenkov et al. (2015). The vertical extent of this red region is also indicative of typical values for the Milky Way (e.g., Figure 10). The shaded gray region indicates the range compatible with observations in M31. The massive (V  c  > 120 km s−1) bulgeless galaxies from Yoachim & Dalcanton (2006) have structural parameters consistent with the Milky Way’s dominant metal-rich disk (Figure 10) but are systematically flatter than what we observe in M31. The disks of galaxies with bulges from Mosenkov et al. (2015) are likewise better analogs of the Milky Way than M31.
Paper: The Panchromatic Hubble Andromeda Treasury. XX. The Disk of M31 is Thick
Authors: Julianne J. Dalcanton, Eric F. Bell, Yumi Choi, Andrew E. Dolphin, Morgan Fouesneau, Léo Girardi, David W. Hogg, Anil C. Seth, Benjamin F. Williams
Figure caption: Observational constraints on the maximum reddening fraction f red and the observed axial ratio for model inclined, thickened disks. The background color indicates the maximum reddenning fraction as shown in Figure 4 (i.e., measured along the minor axis at the surface brightness corresponding to r = 3h  r  for a face-on disk). One set of contours indicates the typical maximum value of f red = 0.803 ± 0.02 observed in M31 (equivalent to the minimum values of f red = 0.197 ± 0.02; see Figure 8). The other set of contours indicates the range of measured axial ratios from Courteau et al. (2011; b/a = 0.27 ± 0.01), derived from their reported ellipticities (ϵ = 0.73 ± 0.01), corresponding to an inclination of i = 74° for an infinitely thin disk. The intersection of these two independent measurements favors a typical disk thickness in the range of h  z /h  r  ≈ 0.15 and a larger true inclination of i ≈ 77°, which is in better agreement with the somewhat larger estimates of the inclination from the tilted-ring fitting of M31's HI velocity field (Chemin et al. 2009; Corbelli et al. 2010).
Paper: The Panchromatic Hubble Andromeda Treasury. XX. The Disk of M31 is Thick
Authors: Julianne J. Dalcanton, Eric F. Bell, Yumi Choi, Andrew E. Dolphin, Morgan Fouesneau, Léo Girardi, David W. Hogg, Anil C. Seth, Benjamin F. Williams
Figure caption: Maps of the dispersion in radius along the line of sight, in units of the radial exponential scale length. The apparent inclinations of the model disks increases from left to right (i = 15°, 30°, 45°, 60°, and 75°), and the disk thickness increases from bottom to top (h  z /h  r  = 0.05, 0.1, 0.15, and 0.2). Away from the major axis, the range of radii probed increases with increasing inclination and disk thickness. This effect will tend to wash out gradients in the measured properties of stellar populations, unless confined to along the major axis.
Paper: A VERITAS/Breakthrough Listen Search for Optical Technosignatures
Authors: A. Acharyya, C. B. Adams, A. Archer, P. Bangale, P. Batista, W. Benbow, A. Brill, M. Capasso, M. Errando, A. Falcone, Q. Feng, J. P. Finley, G. M. Foote, L. Fortson, A. Furniss, S. Griffin, W. Hanlon, D. Hanna, O. Hervet, C. E. Hinrichs, J. Hoang, J. Holder, T. B. Humensky, W. Jin, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, S. Kumar, M. J. Lang, M. Lundy, G. Maier, C. E. McGrath, M. J. Millard, H. R. Miller, J. Millis, C. L. Mooney, P. Moriarty, R. Mukherjee, S. O'Brien, R. A. Ong, M. Pohl, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, J. L. Ryan, I. Sadeh, L. Saha, M. Santander, G. H. Sembroski, R. Shang, D. Tak, A. K. Talluri, J. V. Tucci, N. Vazquez, D. A. Williams, S. L. Wong, J. Woo, D. DeBoer, H. Isaacson, I. de Pater, D. C. Price, A. Siemion
Figure caption: Stellar target locations, in equatorial coordinates, for both the dedicated and archival VERITAS observations. Distance and spectral type are also indicated, as described in the figure legend.
Paper: A VERITAS/Breakthrough Listen Search for Optical Technosignatures
Authors: A. Acharyya, C. B. Adams, A. Archer, P. Bangale, P. Batista, W. Benbow, A. Brill, M. Capasso, M. Errando, A. Falcone, Q. Feng, J. P. Finley, G. M. Foote, L. Fortson, A. Furniss, S. Griffin, W. Hanlon, D. Hanna, O. Hervet, C. E. Hinrichs, J. Hoang, J. Holder, T. B. Humensky, W. Jin, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, S. Kumar, M. J. Lang, M. Lundy, G. Maier, C. E. McGrath, M. J. Millard, H. R. Miller, J. Millis, C. L. Mooney, P. Moriarty, R. Mukherjee, S. O'Brien, R. A. Ong, M. Pohl, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, J. L. Ryan, I. Sadeh, L. Saha, M. Santander, G. H. Sembroski, R. Shang, D. Tak, A. K. Talluri, J. V. Tucci, N. Vazquez, D. A. Williams, S. L. Wong, J. Woo, D. DeBoer, H. Isaacson, I. de Pater, D. C. Price, A. Siemion
Figure caption: Tracks of the CALIPSO transits (in camera coordinates) on 2021 May 17 (top) and 2013 November 11 (bottom) with the location of the average of the image centers in an event shown as blue points. The hexagons correspond to VERITAS pixels. Grayed-out pixels were nonfunctional during the transit for VERITAS telescope 1.
Paper: A VERITAS/Breakthrough Listen Search for Optical Technosignatures
Authors: A. Acharyya, C. B. Adams, A. Archer, P. Bangale, P. Batista, W. Benbow, A. Brill, M. Capasso, M. Errando, A. Falcone, Q. Feng, J. P. Finley, G. M. Foote, L. Fortson, A. Furniss, S. Griffin, W. Hanlon, D. Hanna, O. Hervet, C. E. Hinrichs, J. Hoang, J. Holder, T. B. Humensky, W. Jin, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, S. Kumar, M. J. Lang, M. Lundy, G. Maier, C. E. McGrath, M. J. Millard, H. R. Miller, J. Millis, C. L. Mooney, P. Moriarty, R. Mukherjee, S. O'Brien, R. A. Ong, M. Pohl, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, J. L. Ryan, I. Sadeh, L. Saha, M. Santander, G. H. Sembroski, R. Shang, D. Tak, A. K. Talluri, J. V. Tucci, N. Vazquez, D. A. Williams, S. L. Wong, J. Woo, D. DeBoer, H. Isaacson, I. de Pater, D. C. Price, A. Siemion
Figure caption: Elevated view of the VERITAS array located at the base of Mount Hopkins near Tucson, AZ. Pictured are the four individual telescopes, which are roughly 100 m apart, the Fred Lawrence Whipple Observatory visitor center, and the VERITAS control building (with the white roof). Image from Abeysekara et al. (2016).
Paper: A VERITAS/Breakthrough Listen Search for Optical Technosignatures
Authors: A. Acharyya, C. B. Adams, A. Archer, P. Bangale, P. Batista, W. Benbow, A. Brill, M. Capasso, M. Errando, A. Falcone, Q. Feng, J. P. Finley, G. M. Foote, L. Fortson, A. Furniss, S. Griffin, W. Hanlon, D. Hanna, O. Hervet, C. E. Hinrichs, J. Hoang, J. Holder, T. B. Humensky, W. Jin, P. Kaaret, M. Kertzman, M. Kherlakian, D. Kieda, T. K. Kleiner, N. Korzoun, S. Kumar, M. J. Lang, M. Lundy, G. Maier, C. E. McGrath, M. J. Millard, H. R. Miller, J. Millis, C. L. Mooney, P. Moriarty, R. Mukherjee, S. O'Brien, R. A. Ong, M. Pohl, E. Pueschel, J. Quinn, K. Ragan, P. T. Reynolds, D. Ribeiro, E. Roache, J. L. Ryan, I. Sadeh, L. Saha, M. Santander, G. H. Sembroski, R. Shang, D. Tak, A. K. Talluri, J. V. Tucci, N. Vazquez, D. A. Williams, S. L. Wong, J. Woo, D. DeBoer, H. Isaacson, I. de Pater, D. C. Price, A. Siemion
Figure caption: Schematic illustration of the optical SETI (OSETI) technique with IACT arrays such as VERITAS. Particle air showers, initiated by cosmic-ray particles or gamma-ray photons, produce extended images with parallax shifts when viewed from separated telescopes (left). A distant laser pulse produces identical point-like images, located at the same position in the field of view in each telescope (right).
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Sample color–color and color–magnitude diagrams used to further assess the quality of the YSO candidates. In each plot, small black dots are the ensemble catalog, and larger dots are the YSO candidates. Diagrams like this were used to assess the confidence we had that the YSO candidates were actually YSOs. Anticipating discussion in Section 4.4, the colors of the large dots follow the final YSO rankings. Targets ranked 5 (highest) are blue, 4 are cyan, 3 are green, 2 are orange, and 1 (lowest) are red; the bluer the symbol, the more reliable a YSO candidate it is. Many of the outliers are lower-ranked YSO candidates. The highest-ranked YSOs include both early-type stars and stars without too much JHK  s  reddening or a possible JHK  s  excess ((a); upper left), stars with an IRAC excess ((b); upper right), stars clustered near the 6 Myr model isochrone ((c); lower left), and stars with an Hα excess ((d); lower right). Reddening vectors (following the reddening law from Indebetouw et al. 2008 and Mathis 1990) are as shown. Green solid lines are the expected (empirical) ZAMS relationship. In the JHK  s  plot, the ZAMS is taken from Pecaut & Mamajek (2013), the dashed blue line is the Meyer et al. (1997) T Tauri locus, and the dashed–dotted lines are reddening vectors extending roughly from the green ZAMS relation to give an indication of which of these stars could be reddened MS stars. The green dashed lines in the PanSTARRS plot are 6 and 9 Myr isochrones from PARSEC models (Bressan et al. 2012). The IPHAS ZAMS is from Drew et al. (2005), and the IPHAS data appear quantized due to the precision with which the magnitudes are reported in Hα.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: (a): histogram of A  v  estimates, derived from JHK  s  as discussed in the text. The histogram peaks at ∼100 stars with A  v  ∼ 0 (offscale here). The distribution falls off with A  v , with a max(A  v ) of ∼17 mag. (b): distribution of sources on the sky, with color corresponding to A  v  (redder point is more A  v ). Small dots are sources for which we could not derive an A  v  estimate; larger circles are sources for which we could derive an estimate, and the redder the symbol, the higher the A  v  estimate. Most of the stars have little reddening. Most of the high-A  v  sources are in the NS, but the two with the highest estimate are in Stock 8 (compare to Figures 2 and 5; see Section 6.1 for a zoom-in on just the NS).
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Reverse grayscale images of J052724.69+342049.1, obtained via FinderChart, in 2MASS (top row) and WISE (bottom row); images are 30″ across. The target position is given by the crosshairs, with an additional symbol for the corresponding catalog source. The top right shows an SED with symbols as defined in Table 2. WISE-3 and -4 are both plotted here as limits. The dashed line is the expected flux density from photosphere assuming K s is on the photosphere. This source appears in the AllWISE point-source catalog with high-quality detections in all four WISE bands, but inspection of the image calls WISE-3 and -4 into question. The SED suggests that WISE-3 could be a detection and still be consistent with the rest of the SED; WISE-4 is not physically reasonable. We turned both the WISE-3 and WISE-4 detections into limits based on this image assessment. We retained this source as a YSO candidate; it was in the list of literature YSOs because it appears in Winston et al. (2020).
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Twelve example SEDs, with plot symbols as defined in Table 2. The y-axis is the log of the spectral energy density in cgs units, e.g., erg s−1 cm−2; the x-axis is the log of the wavelength in microns. The black dashed line is a Rayleigh–Jeans line extended from K  s , assuming that K  s  is on the photosphere of the star. The yellow dashed line is a fit to all available detections between 2 and 25 μm. The sources are, from top to bottom, left to right: J052807.89+341842.1, final rank 5, SED Class I; J052858.77+342232.5, final rank 4, SED Class I; J052718.35+344033.4, final rank 5, SED Class flat; J052736.37+344940.6, final rank 4, SED Class flat; J052705.83+343312.0, final rank 5, SED Class II; J052708.88+345031.5, final rank 5, SED Class II; J052717.77+342601.1, final rank 5, SED Class III; J052743.82+344028.0, final rank 4, SED Class III; J052919.14+341747.1, final rank 4*, SED Class flat; J052825.85+342309.6, final rank 4*, SED Class II; J052807.15+342732.3, final rank 2, SED Class II; and J052811.74+341625.0, final rank 3, SED Class III. See the text (and Appendix D) for more discussion.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Reverse grayscale images of J052828.16+342411.7, obtained via FinderChart, in 2MASS (top row) and WISE (bottom row); images are 30″ across. The target position is given by the crosshairs. The top right shows an SED using the existing photometric measurements for this source, four WISE bands (black stars); the dashed line is the expected photosphere if WISE-1 is on the photosphere. This source appears in the AllWISE point-source catalog (red squares in the WISE images) as a high-quality detection; it also appears as a YSO candidate in Winston et al. (2020). However, as can be seen, there is no counterpart at 2MASS (or any other) bands, and the emission at 22 μm is significantly offset from the target position. The SED is inconsistent with that of a YSO. We dropped this source as likely to be a nebular knot, not a YSO.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: (a): Histogram of number of points in the SED created from the catalog merging. Nearly two-thirds of the sources have more than 20 points defining the SED, and just ∼10% have five or fewer points defining the SED. For most sources, we have enough photometry to characterize the object fairly well. (b): Distribution of points on the sky, where the color corresponds to number of points in the SED, where black represents five or fewer points per SED and red represents 35 or more points per SED (color scale shown in plot). Most of the best-populated SEDs are in the best-studied portion of this region, Stock 8. Most of the least-well-populated SEDs are in the NS, where SEDs can be only two IRAC points. (Compare to Figures 2 and 5; see Section 6.1 for zoom-in on just the NS). Given how many points we have in most of the SEDs here, we should be able to make some well-founded assessments of the status of most of these candidate YSOs.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Distribution on the sky of YSO candidates. (In both cases, see Section 6.1 for zoom-in on just the NS.) (a): the YSO quality is color coded the same as in earlier figures: 5 = blue or highest quality, 4 = cyan, 3 = green, 2 = orange, and 1 = red or lowest quality. The clustering in Stock 8 and the NS is obvious by eye; this is a result of how we constructed our candidate list. Many of the lowest-ranked YSOs are in the highest surface density areas (NS and Stock 8) because they have the fewest points in their SEDs. (b): just the rank 3/4/5 stars, and the SED slope is color coded (Class I = red, flat = orange, II = cyan, III = blue). Most of the embedded things are in the NS or Stock 8, but there are some scattered throughout the field. Most of the objects, however, are less embedded.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Histograms of Gaia DR3 parallaxes. (a): the solid line is all YSO candidates; the dotted line is the rest of the catalog, scaled to have the same sample size as the YSO candidate sample. The solid vertical lines are at 1 and 3 kpc, e.g., the range of distances we took to be consistent with IC 417. The numbers on the right and left of the plot indicate how many objects in the member sample fall beyond the ranges of the plot (e.g., there are 13 stars with DR3 parallaxes < − 1). The member sample is more tightly biased toward objects between 1 and 3 kpc; the rest of the catalog is slightly farther away, on average, consistent with it being largely the rest of the Perseus arm population. (b): zoom-in on a smaller range of parallax, with the YSO rank plotted separately, color coded the same as in earlier figures: 5 = blue or highest quality, 4 = cyan, 3 = green, 2 = orange, and 1 = red or lowest rank. The bulk of the YSO candidates that are at the correct distance are largely rank 3, 4, or 5; the YSO candidates that are too close or too far away are largely rank 1 or 2.
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption: Color–color and color–magnitude diagrams as in prior figures; black dots represent the entire catalog, and colored symbols are limited to YSO candidates with rank 3–5. The stars highlighted with red dots are those with IR excess at any band (SED Class < III plus Class IIIs that seem to have an excess at long wavelengths). Additional blue triangles are those with Hα excess. Most YSO candidates with Hα excess also have an IR excess, but relatively few of the IR excess stars have an Hα excess. The stars with IR and/or Hα excesses largely fall where expected in these diagrams—where YSOs are found (also see Appendix C).
Paper: Young Stellar Object Candidates in IC 417
Authors: L. M. Rebull, R. L. Anderson, G. Hall, J. D. Kirkpatrick, X. Koenig, C. E. Odden, B. Rodriguez, R. Sanchez, B. Senson, V. Urbanowski, M. Austin, K. Blood, E. Kerman, J. Long, N. Roosa
Figure caption:  JHK  s  color–color diagrams. Left: the IC 417 sample, as in Figure 11. Small black dots are the ensemble catalog, and larger dots are the YSO candidates. Targets ranked 5 (highest) are blue, 4 are cyan, 3 are green, 2 are orange, and 1 (lowest) are red; the bluer the symbol, the more reliable a YSO candidate it is. Center: Taurus sample of confirmed YSOs. Right: randomly selected adjacent patch of sky near IC 417—e.g., there are unlikely to be YSOs here. In this panel, colors correspond to point density with black/purple being the lowest number of points and orange/red being the highest (the highest density bins are in this case hidden under the green ZAMS line). For all three plots, reddening vectors (following the reddening law from Indebetouw et al. 2008 and Mathis 1990) are as shown. Green solid lines are the expected (empirical) ZAMS relationship. The ZAMS is taken from Pecaut & Mamajek (2013), the dashed blue line is the Meyer et al. (1997) T Tauri locus, and the dashed–dotted lines are reddening vectors extending roughly from the green ZAMS relation to give an indication of which of these stars could be reddened MS stars. Young stars should be clustered near the T Tauri locus and up and to the right, and the Taurus sample is found there. The IC 417 YSO candidate sample is clearly more like the Taurus sample than the targets found in the adjacent patch of sky.