我们使用Ménard et al.（2013）提出的方法研究了基于聚类的红移估计的潜力和准确性。这种技术使推理的红移分布从测量的空间集群的任意源，使用一组参考对象的红移是已知的。我们将其应用于斯隆数字巡天光谱星系的样本，并表明，经过仔细控制的采样效率在天空中，我们可以估计红移分布的高精度。探测的SDSS星系的全色空间，我们表明，我们可以恢复相应的平均红移的精度范围从$δ$ z=0.001到0.01。我们指出，这种映射可以用来推断一个星系的红移概率分布。我们展示了如何缺乏信息的星系偏见限制了推断的准确性，并显示集群红移和光度红移之间的比较，这个数据集。这个分析表明，使用真实的数据，基于聚类的红移推断提供了一个强大的数据驱动的技术来探索任意数据集的红移分布，没有任何先验知识的光谱能量分布的来源。
英文摘要：
We investigate the potential and accuracy of clustering-based redshift estimation using the method proposed by Ménard et al. (2013). This technique enables the inference of redshift distributions from measurements of the spatial clustering of arbitrary sources, using a set of reference objects for which redshifts are known. We apply it to a sample of spectroscopic galaxies from the Sloan Digital Sky Survey and show that, after carefully controlling the sampling efficiency over the sky, we can estimate redshift distributions with high accuracy. Probing the full colour space of the SDSS galaxies, we show that we can recover the corresponding mean redshifts with an accuracy ranging from $δ$z=0.001 to 0.01. We indicate that this mapping can be used to infer the redshift probability distribution of a single galaxy. We show how the lack of information on the galaxy bias limits the accuracy of the inference and show comparisons between clustering redshifts and photometric redshifts for this dataset. This analysis demonstrates, using real data, that clustering-based redshift inference provides a powerful data-driven technique to explore the redshift distribution of arbitrary datasets, without any prior knowledge on the spectral energy distribution of the sources.
An Enhanced Catalog of Gaia DR3 Galaxy Candidates with Spectroscopic and Machine-Learning Photometric Redshifts
Seoul National University（首尔大学）；SNU Astronomy Research Center, Seoul National University（首尔大学天文研究中心）；Institute for Data Innovation in Science, Seoul National University（首尔大学数据科学创新研究所）
Spectroscopic redshifts of selected flat-spectrum radio sources I
Institute of Astrophysics, Foundation for Research and Technology – Hellas（希腊研究与技术基金会天体物理研究所）；University of Crete（克里特大学）；National Institute for Astrophysics (INAF), Astronomical Observatory of Padova（意大利国家天体物理研究所帕多瓦天文台）
Identifying galaxy groups from redshift surveys of galaxies plays an important role in connecting galaxies with the underlying dark matter distribution. Current and future high-$z$ spectroscopic surveys, usually incomplete in redshift sampling, present both opportunities and challenges to identifying groups in the high-$z$ Universe. We develop a group finder that is based on incomplete redshift samples combined with photometric data, using a machine learning method to assign halo masses to identified groups. Test using realistic mock catalogs shows that $\gtrsim 90\%$ of true groups with halo …
In a recent study, we developed a method to model the impact of photometric redshift uncertainty on the two-point correlation function (2PCF). In this method, we can obtain both the intrinsic clustering strength and the photometric redshift errors simultaneously by fitting the projected 2PCF with two integration depths along the line-of-sight. Here we apply this method to the DESI Legacy Imaging Surveys Data Release 8 (LS DR8), the largest galaxy sample currently available. We separate galaxies into 20 samples in 8 redshift bins from $z=0.1$ to $z=1.0$, and a few $\rm z$-band absolute magnitud…
Measuring galaxy environment with the synergy of future photometric and spectroscopic surveys
我们利用低分辨率光谱学和光度红移之间的协同作用，研究环境对星系演化的影响，从空间的无缝光谱调查。作为一个测试案例，我们考虑未来的欧几里得深调查（~ 40度$^2$），它结合了一个无狭缝光谱调查有限的H $α$通量$\geq5\times 10^{-17}$ erg cm $^{-2}$ s $^{-1}$和测光调查有限的H波段（$H\leq26$）。我们使用欧几里德星系模拟目录，在其中我们锚定的光度红移可用的光谱红移的三维星系分布。然后，我们估计的局部密度对比度的计数对象的半径从1到10 h $^{-1}$ Mpc的红移范围0.9<z<1.8的圆柱形细胞。我们比较这个密度场与一个模拟目录中计算的深度相同的欧几里德深调查（H=26），但没有红移测量误差。我们发现，我们的方法成功地从低密度环境（最后从第一个五分之一的密度分布），在低红移和大细胞的效率更高：低密度区域的分数错误的高密度峰是<1%的所有尺度和红移探索，但1小时$^{-1}$ Mpc的尺度，这是几个百分点。这些结果表明，我们可以有效地研究环境中的光度样本，如果光谱信息是一个较小的样本的对象，稀疏采样相同的体积。我们证明，这些研究是可能的欧几里得深调查，即在红移范围内的环境影响是不同于在本地宇宙中观察到的，从而为星系演化模型提供了新的约束。
We present Keck spectroscopic observations of three probable high redshift superluminous supernovae (SLSNe) from the Subaru HIgh-Z sUpernova CAmpaign (SHIZUCA), confirming redshifts of 1.851, 1.965 and 2.399. The host galaxies were selected for transient monitoring from multi-band photometric redshifts. The supernovae are detected during their rise, and the classically scheduled spectra are collected near maximum light. The restframe far-ultraviolet (FUV;$\sim$1000A-2500A) spectra include a significant host galaxy flux contribution and we compare our host galaxy subtracted spectra to UV-lumino…
We present new spectroscopic data of the BL Lac RGB 2243+203, and its surroundings, obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted in the Gran Telescopio Canarias (GTC). The spectra of neither the BL Lac nor its host galaxy show any spectral feature, thus hindering direct determination of its redshift. The spectroscopic redshift distribution of objects in the MOS field of view shows four galaxies with redshift between 0.5258 and 0.5288. We make use of a statistical analysis to test the possibility that the targeted BL Lac may be a member of that group. By using the spectrosco…
Improving distance measurements in large imaging surveys is a major challenge to better reveal the distribution of galaxies on a large scale and to link galaxy properties with their environments. Photometric redshifts can be efficiently combined with the cosmic web (CW) extracted from overlapping spectroscopic surveys to improve their accuracy. We apply a similar method using a new generation of photometric redshifts based on a convolution neural network (CNN). The CNN is trained on the SDSS images with the main galaxy sample (SDSS-MGS, $r \leq 17.8$) and the GAMA spectroscopic redshifts up to…
This paper presents stellar mass functions and i-band luminosity functions for Sloan Digital Sky Survey (SDSS) galaxies at $i < 21$ using clustering redshifts, from which we also compute targeting completeness measurements for the Baryon Oscillation Spectroscopic Survey (BOSS). Clustering redshifts is a method of obtaining the redshift distribution of a sample of galaxies with only photometric information by measuring the angular crosscorrelation with a spectroscopic sample in different redshift bins. We construct a spectroscopic sample containing data from the BOSS + eBOSS surveys, allowing u…
The NIRISS PASSAGE Spectroscopic Redshift Catalog in COSMOS
University of Minnesota, Twin Cities（明尼苏达大学双城分校）；California Institute of Technology（加州理工学院）；Johns Hopkins University（约翰斯·霍普金斯大学）；Space Telescope Science Institute（太空望远镜科学研究所）；Stockholm University（斯德哥尔摩大学）
Accurate spectroscopic redshift estimation using non-negative matrix factorization: application to MUSE spectra
Université Claude Bernard Lyon 1, Ens de Lyon, CNRS, Centre de Recherche Astrophysique de Lyon (CRAL)（里昂第一大学、里昂高等师范学校、法国国家科学研究中心、里昂天体物理研究中心）；Leibniz-Institut für Astrophysik Potsdam (AIP)（波茨坦莱布尼茨天体物理研究所）；Instituto de Astrofísica e Ciências do Espaço, Universidade do Porto, CAUP（太空天文与物理学研究所、波尔图大学、波尔图天文台）；Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto（波尔图大学理学院物理与天文系）；Institut für Physik und Astronomie, Universität Potsdam（波茨坦大学物理与天文研究所）；National Astronomical Observatory of Japan（日本国立天文台）
We publicly release the spectroscopic and photometric redshift catalog of the sources detected with Chandra in the field of the $z$=6.3 quasar SDSS J1030+0525. This is currently the fifth deepest X-ray field, and reaches a 0.5-2 keV flux limit $f_{\rm 0.5-2}$=6$\times$10$^{-17}$ erg s$^{-1}$ cm$^{-2}$. By using two independent methods, we measure a photometric redshift for 243 objects, while 123 (51%) sources also have a spectroscopic redshift, 110 of which coming from an INAF-Large Binocular Telescope (LBT) Strategic Program. We use the spectroscopic redshifts to determine the quality of the …
In this study we present a new experimental design using clustering-based redshift inference to measure the evolving galaxy luminosity function (GLF) spanning 5.5 decades from $L \sim 10^{11.5}$ to $ 10^6 ~ \mathrm{L}_\odot$. We use data from the Galaxy And Mass Assembly (GAMA) survey and the Kilo-Degree Survey (KiDS). We derive redshift distributions in bins of apparent magnitude to the limits of the GAMA-KiDS photometric catalogue: $m_r \lesssim 23$; more than a decade in luminosity beyond the limits of the GAMA spectroscopic redshift sample via clustering-based redshift inference. This tech…
We present a spectroscopic survey of Ly$α$ emitters (LAEs) at $z\approx5.7$ using the multi-object spectrograph M2FS on the Magellan Clay telescope. This is part of a high-redshift galaxy survey carried out in several well-studied deep fields. These fields have deep images in multiple UV/optical bands, including a narrow NB816 band that has allowed an efficient selection of LAE candidates at $z\approx5.7$. Our sample consists of 260 LAEs and covers a total effective area of more than two square degrees on the sky. This is so far the largest (spectroscopically confirmed) sample of LAEs at this …
Using the EMIR instrument on the IRAM 30m telescope, we conducted a spectroscopic redshift search of seven z$_{\rm phot}$ $\sim$ 4 sub-millimetre bright galaxies selected from the Herschel Bright Sources (HerBS) sample with fluxes at 500 $μ$m greater than 80 mJy. For four sources, we obtained spectroscopic redshifts between 3.4 < z < 4.1 through the detection of multiple CO-spectral lines with J $\leq$ 3. Later, we detected low-J transitions for two of these sources with the GBT including the CO(1-0) transition. For the remaining three sources, more data are needed to determine the spectroscop…
We spectroscopically confirmed two narrow-band selected redshift 7.0 Ly$α$ galaxies and studied their restframe UV spectra. The Ly$α$ and other UV nebular lines are very useful to confirm the galactic redshifts and diagnose the different mechanisms driving the ionizing emission. We observed two narrowband-selected $z$=7.0 Ly$α$ candidates in the LAGER Chandra Deep Field South (CDFS) field with IMACS at Magellan telescope and confirmed they are Ly$α$ emitters at $z$=6.924 and 6.931. In one galaxy, we also obtained deep NIR spectroscopy, which yields non-detections of the high-ionization UV nebu…
