Deep Near-Infrared Survey Toward the W40 and Serpens South Region in Aquila Rift: The 2MASS-UKIDSS-CFHT Near-infrared Catalog

We use Wide-Field Infrared Camera (WIRCam) at the CFHT to take NIR images of the W40 and the Serpens South at the J, H, and Ks bands. Observations were carried out in the J, H, and Ks bands between 2012 July 27 and 29 by Wide-Field Infrared Camera (WIRCam) at the CFHT, which has a field of view of 20'× 20', and a resolution of 0.3" per pixel. The NIR data covers a "Target" field centered at ~ 18:30:30, -2:00:00 and size of ~ 60'*80', and a "Control" field centered at ~ 18:33:24, -1:03:00 and size of ~ 20'*20'. Average full width at half-maximum (FWHM) of sub-fields varies from 0.45" to 0.96". Single image exposure time of J, H, and Ks is 30, 10.3 and 15 s, respectively. Each sub-field is covered by 4–24 exposures, and about 70% of the final integrated images contain more than 16 exposures. Total exposure time reaches 240, 123.6, and 120 s on average, in the J, H, and Ks bands, respectively.Raw images are processed by CFHT’s IDL Interpreter of the WIRCam Images, which is the 'I'wii pipeline. In the pipeline, following processes are performed automatically: chipbias and dark subtraction, flat-fielding, non-linearity correction, cross-talk removal and sky subtraction. Pixels that are bad or saturated are also marked. We adopt the 'Astromatic' suite and optimize the reduction processes to obtain precise images for photometry. Multiple corrections are applied to these photometry results, such as that for optics astigmatism and telescope spikes, color term fitting, and zero magnitude correction. We use PhotVis (Gutermuth et al. 2008b) to identify stars and perform aperture photometry, and also perform the images on SExtractor to assist the evaluation. The radius of aperture, inner and outer radii of the background annulus are chosen to be 0.75", 1.5", and 3". We identify sources with statistics better than 6 S/N ratio.We present our results in this table. It contains 910,275 stars in the W40 - Serpens South Region with Near-infrared (NIR) photometry data from CFHT observation supplemented by 2MASS and UKIDSS. The table has 40 columns, with their headers listed as follows: 1.RA_J2000, 2.DEC_J2000, 3.J_CFHT, 4.JERR_CFHT, 5.H_CFHT, 6.HERR_CFHT, 7.K_CFHT, 8.KERR_CFHT, 9.J_NN, 10.H_NN,11.K_NN, 12.D_JNN, 13.D_HNN, 14.D_KNN, 15.FWHM_J, 16.FWHM_H, 17.FWHM_K, 18.Field, 19.AK_FRONT, 20.AK_TOTAL, 21.SEx_Ellip_J, 22.SEx_Ellip_H, 23.SEx_Ellip_K, 24.Flag_J, 25.Flag_H, 26.Flag_K, 27.J_UKIDSS, 28.JERR_UKIDSS, 29.H_UKIDSS, 30.HERR_UKIDSS, 31.K_UKIDSS, 32.KERR_UKIDSS, 33.RA_2MASS, 34.DEC_2MASS, 35.J_2MASS, 36.JERR_2MASS, 37.H_2MASS, 38.HERR_2MASS, 39.K_2MASS, 40.KERR_2MASSTheir units are as follows:1. Degrees (0~360), 2. Degrees (-90,90), 3.mag, 4.mag, 5.mag, 6.mag, 7.mag, 8.mag, 9.mag, 10.mag, 11.mag, 12.arcsec, arcsec, 13.arcsec, 14.arcsec, 15.arcsec, 16.arcsec, 17.arcsec, 18.0-10, 19.mag, 20.mag, 21.unitless, 22.unitless, 23.unitless, 24.0-16, 25.0-16, 26.0-16, 27.mag, 28.mag, 29.mag, 30.mag, 31.mag, 32.mag, 33. Degrees (0~360), 34. Degrees (-90,90), 35.mag, 36.mag, 37.mag, 38.mag, 39.mag, 40.magMissing data for all columns are set with -1.0, including the 34th column, DEC_2MASS, which has values both > -1.0 and < -1.0. The corresponding physical meanings and some explanations are as follows:1. Ra (J2000) of CFHT stars; 2. Dec (J2000) of CFHT stars; 3. J magnitude of CFHT stars; 4. J magnitude uncertainty of CFHT stars; 5. H magnitude of CFHT stars; 6. H magnitude uncertainty of CFHT stars; 7. K magnitude of CFHT stars; 8. K magnitude uncertainty of CFHT stars; 9. J magnitude of the star's J band nearest neighbor; 10. H magnitude of the star's H band nearest neighbor; 11. K magnitude of the star's K band nearest neighbor; 12. Distance of the star's J band nearest neighbor; 13. Distance of the star's H band nearest neighbor; 14. Distance of the star's K band nearest neighbor; 15. star's full width at half maximum on J band image; 16. star's full width at half maximum on H band image; 17. star's full width at half maximum on K band image; 18. the field number of stars observed by CFHT, 0 means in the "Control" field, and 1-10 means in parts of the "Target" field; 19. dereddening magnitude AK (also called 'FRONT' extinction), adopting the left of Figure 17 in Gutermuth et al. 2009 which only uses J, H and K band; 20. extinction magnitude in K band (so-called 'AK TOTAL'): for the "Target" field it is converted from Herschel column density map, using NH/AV = 1.8 * 10^21 cm−2/mag (Predehl & Schmitt 1995) and AK/AV = 0.112 (Rieke & Lebofsky 1985). For the "Control" field we use 2MASS extinction map, multiplied by a factor of 1/1.22, which is the ratio between the median value of Herschel and 2MASS extinction map in the "Target"; 21. Ellipticity on CFHT image reported by SExtractor in J band, calculated by E=1-B/A, in which A is semi-major axis, and B is semi-minor axis; 22. Ellipticity on CFHT image reported by SExtractor in H band; 23. Ellipticity on CFHT image reported by SExtractor in K band; 24. Star quality flag on CFHT image in J band: +1 = SExtractor reported "blended", +2 = other SExtractor problem flags or not found by SExtractor, +4 = nearby a bright star, +8 = sits on corner of bright star, +16 = has saturated/NAN/negative point nearby star's center on the CFHT image; 25. Star quality flag on CFHT image in H band; 26. Star quality flag on CFHT image in K band; 27. J magnitude from UKIDSS data; 28. J magnitude uncertainty from UKIDSS data; 29. H magnitude from UKIDSS data; 30. H magnitude uncertainty from UKIDSS data; 31. K magnitude from UKIDSS data; 32. K magnitude uncertainty from UKIDSS data; 33. Ra (J2000) from 2MASS data; 34. Dec (J2000) from 2MASS data; 35. J magnitude from 2MASS data; 36. J magnitude uncertainty from 2MASS data; 37. H magnitude from 2MASS data; 38. H magnitude uncertainty from 2MASS data; 39. K magnitude from 2MASS data; 40. K magnitude uncertainty from 2MASS data.

我们使用加拿大-法国-夏威夷望远镜(CFHT)搭载的宽视场红外相机(Wide-Field Infrared Camera, WIRCam)，对W40与南巨蛇座(Serpens South)天区开展J、H、Ks波段的近红外(NIR)成像观测。本次观测于2012年7月27日至29日完成，该相机视场为20′×20′，像素分辨率为0.3角秒每像素。

本次近红外数据覆盖两个天区：“靶场(Target)天区”，中心坐标约为18:30:30，-2:00:00，尺寸约60′×80′；以及“对照场(Control)天区”，中心坐标约为18:33:24，-1:03:00，尺寸约20′×20′。子天区的平均半高全宽(FWHM)介于0.45角秒至0.96角秒之间。

J、H、Ks波段的单帧曝光时间分别为30s、10.3s与15s。每个子天区被4~24帧曝光覆盖，最终合成的积分图像中约70%拥有超过16帧的叠加曝光。J、H、Ks波段的总平均曝光时间分别达到240s、123.6s与120s。

原始图像通过CFHT官方的WIRCam图像IDL处理脚本——即'I'wii流水线进行校准。该流水线自动完成以下流程：芯片偏置与暗场扣除、平场校正、非线性校正、串扰去除与天空背景扣除，同时标记坏像素与饱和像素。我们采用Astromatic软件套件并优化约减流程，以获得用于测光的高精度图像。我们对测光结果进行了多重校正，包括光学像散与望远镜衍射尖峰校正、色项拟合与零星等校正。

我们使用PhotVis（Gutermuth等人，2008b）进行恒星识别与孔径测光，并通过SExtractor对图像进行处理以辅助评估。孔径半径、背景环的内外半径分别选取为0.75角秒、1.5角秒与3角秒。我们筛选出信噪比(S/N)优于6的天体作为有效源。

本数据集以表格形式呈现，包含W40-南巨蛇座天区共910275颗恒星的近红外测光数据，这些数据来自CFHT观测，并补充了2MASS与UKIDSS的测光数据。该表格共包含40列，表头依次为：1.RA_J2000，2.DEC_J2000，3.J_CFHT，4.JERR_CFHT，5.H_CFHT，6.HERR_CFHT，7.K_CFHT，8.KERR_CFHT，9.J_NN，10.H_NN，11.K_NN，12.D_JNN，13.D_HNN，14.D_KNN，15.FWHM_J，16.FWHM_H，17.FWHM_K，18.Field，19.AK_FRONT，20.AK_TOTAL，21.SEx_Ellip_J，22.SEx_Ellip_H，23.SEx_Ellip_K，24.Flag_J，25.Flag_H，26.Flag_K，27.J_UKIDSS，28.JERR_UKIDSS，29.H_UKIDSS，30.HERR_UKIDSS，31.K_UKIDSS，32.KERR_UKIDSS，33.RA_2MASS，34.DEC_2MASS，35.J_2MASS，36.JERR_2MASS，37.H_2MASS，38.HERR_2MASS，39.K_2MASS，40.KERR_2MASS。

各列单位如下：1. 度（0~360），2. 度（-90~90），3. 星等(mag)，4. 星等(mag)，5. 星等(mag)，6. 星等(mag)，7. 星等(mag)，8. 星等(mag)，9. 星等(mag)，10. 星等(mag)，11. 星等(mag)，12. 角秒(arcsec)，13. 角秒(arcsec)，14. 角秒(arcsec)，15. 角秒(arcsec)，16. 角秒(arcsec)，17. 角秒(arcsec)，18. 0~10，19. 星等(mag)，20. 星等(mag)，21. 无量纲，22. 无量纲，23. 无量纲，24. 0~16，25. 0~16，26. 0~16，27. 星等(mag)，28. 星等(mag)，29. 星等(mag)，30. 星等(mag)，31. 星等(mag)，32. 星等(mag)，33. 度（0~360），34. 度（-90~90），35. 星等(mag)，36. 星等(mag)，37. 星等(mag)，38. 星等(mag)，39. 星等(mag)，40. 星等(mag)。

所有列的缺失数据均以-1.0填充，包括第34列DEC_2MASS，该列存在大于-1.0与小于-1.0的有效取值。

各列对应的物理含义与补充说明如下：1. CFHT观测恒星的J2000赤经(RA)；2. CFHT观测恒星的J2000赤纬(DEC)；3. CFHT测光得到的J波段星等；4. CFHT测光得到的J波段星等不确定度；5. CFHT测光得到的H波段星等；6. CFHT测光得到的H波段星等不确定度；7. CFHT测光得到的K波段星等；8. CFHT测光得到的K波段星等不确定度；9. 目标恒星J波段最近邻天体的J波段星等；10. 目标恒星H波段最近邻天体的H波段星等；11. 目标恒星K波段最近邻天体的K波段星等；12. 目标恒星与J波段最近邻天体的角距离；13. 目标恒星与H波段最近邻天体的角距离；14. 目标恒星与K波段最近邻天体的角距离；15. 恒星在J波段图像上的半高全宽；16. 恒星在H波段图像上的半高全宽；17. 恒星在K波段图像上的半高全宽；18. CFHT观测对应的天区编号：0代表“对照场”，1~10代表“靶场天区”的子区域；19. 消光校正后的K波段星等AK（又称“FRONT消光”），采用Gutermuth等人2009年研究中图17左侧仅使用J、H、K波段的校正方案；20. K波段总消光星等（即“AK_TOTAL”）：对于“靶场天区”，通过赫歇尔(Herschel)柱密度图转换得到，采用NH/AV = 1.8×10^21 cm^-2 mag^-1（Predehl & Schmitt 1995）与AK/AV = 0.112（Rieke & Lebofsky 1985）的转换关系；对于“对照场”，我们采用2MASS消光图，并乘以因子1/1.22，该因子为“靶场天区”内赫歇尔与2MASS消光图的中值之比；21. SExtractor在J波段对CFHT图像测得的椭圆度，定义为E=1-B/A，其中A为半长轴，B为半短轴；22. SExtractor在H波段对CFHT图像测得的椭圆度；23. SExtractor在K波段对CFHT图像测得的椭圆度；24. CFHT图像J波段的恒星质量标志：+1代表SExtractor判定为“混叠源”，+2代表SExtractor其他异常标志或未被SExtractor识别，+4代表邻近亮星，+8代表位于亮星的边缘区域，+16代表恒星中心附近存在饱和、非数值(NAN)或负值像素点；25. CFHT图像H波段的恒星质量标志；26. CFHT图像K波段的恒星质量标志；27. UKIDSS测光得到的J波段星等；28. UKIDSS测光得到的J波段星等不确定度；29. UKIDSS测光得到的H波段星等；30. UKIDSS测光得到的H波段星等不确定度；31. UKIDSS测光得到的K波段星等；32. UKIDSS测光得到的K波段星等不确定度；33. 2MASS测光得到的J2000赤经；34. 2MASS测光得到的J2000赤纬；35. 2MASS测光得到的J波段星等；36. 2MASS测光得到的J波段星等不确定度；37. 2MASS测光得到的H波段星等；38. 2MASS测光得到的H波段星等不确定度；39. 2MASS测光得到的K波段星等；40. 2MASS测光得到的K波段星等不确定度。