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J/AJ/154/57     New SDSS and Washington photometry in Segue 3    (Hughes+, 2017)

A multiwavelength study of the Segue 3 cluster. Hughes J., Lacy B., Sakari C., Wallerstein G., Davis C.E., Schiefelbein S., Corrin O., Joudi H., Le D., Haynes R.M. <Astron. J., 154, 57-57 (2017)> =2017AJ....154...57H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Radial velocities ; Photometry, ugriz ; Photometry, CMT1T2V ; Stars, masses ; Stars, ages ; Effective temperatures ; Abundances, [Fe/H] Keywords: globular clusters: individual: Segue 3 Abstract: We present new SDSS and Washington photometry of the young outer-halo stellar system Segue 3. Combined with archival VI-observations, our most consistent results yield Z=0.006±0.001, log(Age)=9.42±0.08, (m-M)0=17.35±0.08, and E(B-V)=0.09±0.01, with a high binary fraction of 0.39±0.05 derived using the Padova models. We confirm that mass-segregation has occurred, supporting the hypothesis that this cluster is being tidally disrupted. A three-parameter King model yields a cluster radius of rcl=0.017°±0.007°, a core radius of rc=0.003°±0.001°, and a tidal radius of rt=0.04°±0.02°. A comparison of Padova and Dartmouth model-grids indicates that the cluster is not significantly α-enhanced, with a mean [Fe/H]=-0.55-0.12+0.15dex, and a population age of only 2.6±0.4Gyr. We rule out a statistically significant age spread at the main-sequence turnoff because of a narrow subgiant branch, and discuss the role of stellar rotation and cluster age, using Dartmouth and Geneva models: approximately 70% of the Seg 3 stars at or below the main-sequence turnoff have enhanced rotation. Our results for Segue 3 indicate that it is younger and more metal-rich than all previous studies have reported to date. From colors involving Washington C and SDSS-u filters, we identify several giants and a possible blue straggler for future follow-up spectroscopic studies, and we produce spectral energy distributions of previously known members and potential Segue 3 sources with Washington (CT1), Sloan (ugri), and VI-filters. Segue 3 shares the characteristics of unusual stellar systems that have likely been stripped from external dwarf galaxies as they are being accreted by the Milky Way, or that have been formed during such an event. Its youth, metallicity, and location are all inconsistent with Segue 3 being a cluster native to the Milky Way. Description: We used the Apache Point Observatory (APO) new Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) imager and the camera it replaced, Seaver Prototype Imaging camera (SPIcam) for our observations with the 3.5m telescope. The ARCTIC camera has a 4096*4096 STA chip giving 7.5'*7.5' as the FOV when the new 5-inch diameter circular filters are used. The older Washington filters are 3''*3'' and vigniette the FOV. SPIcam had a FOV of 4.8'*4.8'. We have several filter wheels that can handle up to ten 3*3 inch square filters (fewer in full-field mode), where binning 1*1 yields 0.11arcseconds/pixel. The fastest readout time in 2*2 binned mode is about 5s. The blue-UV sensitivity of ARCTIC is greater than that of SPIcam, which was a backside-illuminated SITe TK2048E 2048*2048 pixel CCD with 24 micron pixels, which we also binned (2*2), giving a plate scale of 0.28 arcsec per pixel. Where we combined the data sets, we binned ARCTIC 2*2 and slightly degraded its resolution. We found no irreducible color terms between frames taken with both imagers, internally. From 2013 to 2015, we had 11 half-nights total, and 102 frames had seeing better than 2'', many of which were under photometric conditions, and several nights had subarcsecond seeing. Some of the observations were repeated between SPIcam and ARCTIC, which served to test the new imager. We observed Seg 3 in the Washington filters (Canterna 1976AJ.....81..228C) C and T1 and SDSS ugri filters with both SPIcam and ARCTIC. The frames used are listed in Table1, the overlap between this paper and the Vr-data from Fadely et al. 2011 (Cat. J/AJ/142/88) (not the g and r mag values) and Ortolani et al. 2013 (Cat. J/MNRAS/433/1966) is detailed in Table2. Our photometry is presented in Table3 for all 218 objects detected in our field-of-view in CT1ugri-filters, where we required detections in all filters in order to produce spectral energy distributions (SEDs). We include the z-filter from SDSS DR13 and any 2MASS objects detected, for completeness. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 34 102 Frames used table2.dat 83 218 Cross-identification of objects in the Segue 3 field table3.dat 92 218 Segue 3: sources with detections in all filters table5.dat 65 14 Input for Hertzsprung-Russell (H-R) diagrams for the photometric sample above the Main-Sequence TurnOff (MSTO)
See also: V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015) J/MNRAS/439/788 : Stromgren and Washington photometry in Boo I (Hughes+, 2014) J/MNRAS/433/1966 : Segue 3 VI photometry (Ortolani+, 2013) J/ApJ/740/106 : Abundances of 4 red giants in Pal 1 (Sakari+, 2011) J/AJ/142/88 : Segue 3 photometric and kinematic data (Fadely+, 2011) J/AJ/136/2321 : Washington photometry of Bootes I stars (Hughes+, 2008) J/AJ/134/229 : CT1T2 Photometry of red giants in globulars (Hughes+, 2007) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 10 A10 "Y:M:D" Date Date of the observation 12- 17 A6 --- Imager Imager used in observation (ARCTIC or SPICam) (1) 19 A1 --- Filter Filter used in observation (C, R, u, g, r, or i) (2) 21- 24 I4 s Texp [30/1800] Exposure time 26- 30 F5.3 --- Airmass [1/2.37] Effective airmass 32- 34 F3.1 arcsec FWHM [0.5/1.7] Image Full-Width at Half-Maximum
Note (1): The instrument identifiers are defined as follows: ARCTIC = Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) at Apache Point Observatory (APO); SPICam = Seaver Prototype Imaging camera (SPIcam) at APO. Note (2): We observed Seg 3 in the Washington filters C and T1 and SDSS ugri filters (R is converted to Washington T1).
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Object [2/304] Internal identifier (ID) 5- 23 A19 --- SDSS SDSS DR13 identifier 25 A1 --- f_SDSS Photometric quality grade on SDSS (A, B, C, D, F, or G) (1) 27- 36 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000) 38- 46 F9.6 deg DEdeg Declination in decimal degrees (J2000) 48- 54 F7.3 pix Xpix [17.9/898.9] X pixel coordinate (XC) (2) 56- 62 F7.3 pix Ypix [6/732.78] Y pixel coordinate (YC) (2) 64- 69 F6.1 km/s RV [-353.7/28.8]? Radial velocity (Vr) 71- 76 F6.3 mag Imag [14.27/23.45]? Apparent I band magnitude (IO13) (3) 78- 83 F6.3 mag Vmag [15.19/24.23]? Apparent V band magnitude (VO13) (3)
Note (1): SDSS DR13 photometric quality grade are defined as follows: A = Warning flag; B = Warning flag; C = Warning flag; D = Untrustworthy; F = Untrustworthy; G = Galaxy. Note (2): From Figures 3(b) and 9. Note (3): From Ortolani, Bica & Barbuy 2013 (Cat. J/MNRAS/433/1966).
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Object [2/304] Internal identifier (ID) 5- 10 F6.3 mag T1mag [14/23.79] Apparent T1 band magnitude (4) 12- 16 F5.3 mag e_T1mag [0.004/0.1] The 1σ uncertainty in T1mag 18- 23 F6.3 mag Cmag [15.15/26.2] Apparent C band magnitude (4) 25- 29 F5.3 mag e_Cmag [0.007/0.54] The 1σ uncertainty in Cmag 31- 36 F6.3 mag umag [16.55/25.75] Apparent u band magnitude (4) 38- 42 F5.3 mag e_umag [0.009/0.59] The 1σ uncertainty in umag 44- 49 F6.3 mag gmag [14.61/25.54] Apparent g band magnitude (4) 51- 55 F5.3 mag e_gmag [0.004/0.38] The 1σ uncertainty in gmag 57- 62 F6.3 mag rmag [13.92/24.3] Apparent r band magnitude (4) 64- 68 F5.3 mag e_rmag [0.01/0.2] The 1σ uncertainty in rmag 70- 75 F6.3 mag imag [13.86/35.77] Apparent i band magnitude (4) 77- 81 F5.3 mag e_imag [0.017/0.27] The 1σ uncertainty in imag 83- 87 F5.2 mag zmag [14/23.1]? Apparent SDSS DR13 catalog z band magnitude 89- 92 F4.2 mag e_zmag [0.01/0.95]? The 1σ uncertainty in zmag
Note (4): We used the Apache Point Observatory (APO) new Astrophysical Research Consortium Telescope Imaging Camera (ARCTIC) and the camera it replaced, Seaver Prototype Imaging camera (SPIcam) for our observations with the 3.5m telescope. We observed Seg 3 in the The Washington filters (Canterna 1976AJ.....81..228C) C and T1 and SDSS ugri filters.
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
1- 3 I3 --- Object [6/273] Internal identifier (ID) 5 A1 --- f_Object [a] Flag on Object (1) 7- 10 F4.2 --- logA [5.1/9.5] Log of age log(Age) 12 A1 --- f_logA [b] Flag on logA (1) 14- 19 F6.4 --- Z [0.004/0.005] Metallicity 21- 26 F6.4 [K] logT [3.68/4.1] Log of effective temperature (logTeff) 28- 32 F5.3 [Sun] logL [0.86/2.28] Log of luminosity (logL/L) 34- 38 F5.3 --- logg [2.35/4.31] Log of surface gravity 40- 45 F6.4 [Sun] Mass [1.32/2.63] Mass (M/M) 47- 65 A19 --- Com Comments
Note (1): Flag defined as follows: a = Identified by Vr in Fadely et al. 2011 (Cat. J/AJ/142/88); b = Young age estimate. Blue straggler (BS) or evolved BS?
History: From electronic version of the journal
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 27-Oct-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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