Lenticular galaxies (S0s) were considered mainly as passive evolved spirals due to environmental effects for a long time; however, most S0s in the field cannot fit into this common scenario. In this work, we study one special case, SDSS J120237.07+642235.3 (PGC 38025), a star-forming field S0 galaxy with an off-nuclear blue core. We present optical integral field spectroscopic (IFS) observation with the 3.5 meter telescope at Calar Alto (CAHA) Observatory, and high-resolution millimeter observation with the NOrthern Extended Millimeter Array (NOEMA). We estimated the star formation rate (SFR = 0.446 $M_\odot yr^{-1}$) and gaseous metallicity (12 + log(O/H) = 8.42) for PGC 38025, which follows the star formation main sequence and stellar mass - metallicity relation. We found that the ionized gas and cold molecular gas in PGC 38025 show the same spatial distribution and kinematics, whilst rotating misaligned with stellar component. The off-nuclear blue core is locating at the same redshift as PGC 38025 and its optical spectrum suggest it is \rm H\,{\sc ii} region. We suggest that the star formation in PGC 38025 is triggered by a gas-rich minor merger, and the off-nuclear blue core might be a local star-formation happened during the accretion/merger process.
Comparing to the inactive and gas-poor normal lenticular galaxies (S0s) in the local universe, we study a barred star-forming S0 galaxy, PGC 34107, which has been observed by the Centro Astronómico Hispano Alemán (CAHA) 3.5-m telescope and the Northern Extended Millimeter Array (NOEMA). The spatially resolved ionized gas and molecular gas traced by $^{12}$CO(1-0), hereafter CO(1-0), show the similar distribution and kinematics to the stellar component with an off-center star-forming region, $\sim$380 pc away from the center. The resolved kinematics of molecular CO(1-0) emission reveals that th…
We take advantage of exquisitely deep optical imaging data from HST/ACS in the F475W ($g_{F475W}$) and F606W ($V_{F606W}$) bands, to study the properties of the globular cluster (GC) population in the intermediate mass lenticular galaxy PGC 087327, in the Hydra I galaxy cluster. We inspect the photometric (magnitudes and color) and morphometric (compactness, elongation, etc.) properties of sources lying in an area of $\sim19\times19$ kpc centered on PGC 087327, and compare them with four neighbouring fields over the same HST/ACS mosaic. This allowed us to identify a list of GC candidates and t…
Lenticular galaxies are generally thought to have descended from spirals via morphological transformation, although recent numerical simulations have shown that minor or even major merger can also lead to an S0-like remnant. These mechanisms, however, are active in a dense environment such as a group or a cluster of galaxies - making it harder to explain the remarkable fraction of S0s found in the field. Here, we propose a new mechanism to form such lenticular galaxies. We show that an isolated cold disk settled into rotational equilibrium becomes violently unstable - leading to fragmentation …
Rings in S0s are enigmatic features which can however betray the evolutionary paths of particular galaxies. We have undertaken long-slit spectroscopy of five lenticular galaxies with UV-bright outer rings. The observations have been made with the Southern African Large Telescope (SALT) to reveal the kinematics, chemistry, and the ages of the stellar populations and the gas characteristics in the rings and surrounding disks. Four of the five rings are also bright in the H-alpha emission line, and the spectra of the gaseous rings extracted around the maxima of the H-alpha equivalent width reveal…
AstroSat-UVIT observations of a possibly interacting pair of galaxies in HCG 77
Indian Institute of Science Education and Research, Mohali（印度科学教育研究所穆哈利分校）；Thapar Institute of Engineering and Technology, Patiala（塔帕尔工程技术学院帕蒂亚拉分校）；Tata Institute of Fundamental Research, Mumbai（塔塔基础研究所孟买分校）
We present 2D-spectroscopic observations from Centro Astronómico Hispano Alemán (CAHA) 3.5 m telescope and the millimetre observation from NOrthern Extended Millimeter Array (NOEMA) of the nearby S0 galaxy PGC 26218, which shows central star-formation activity and post-starburst outside in the disk. We estimate the star formation rate (SFR = $0.28\pm0.01$ $M_{\odot} \rm yr^{-1}$) and molecular gas mass ($\rm log\ $$M_{\rm H_{2}}=7.60\pm0.15\ M_{\odot}$) of PGC 26218 based on the extinction-corrected H$α$ emission line and the CO-$\rm H_{2}$ conversion factor ($α_{\rm CO}$) of the Milky Way, re…
We present the results of our study of starforming regions in the lenticular galaxy NGC 4324. During a complex analysis of multiwavelength observational data -- the narrow-band emission-line images obtained with the 2.5-m telescope at the Caucasus Mountain Observatory of the Sternberg Astronomical Institute of the Moscow State University and the archival images in the broad bands of the SDSS, GALEX and WISE surveys -- we have detected young starforming complexes (clumps) located in the inner ring of the lenticular galaxy NGC 4324, and we have established a regular pattern of their distribution…
In order to understand the initial conditions and early evolution of star formation in a wide range of Galactic environments, we carried out an investigation of 64 \textit{Planck} Galactic Cold Clumps (PGCCs) in the second quadrant of the Milky Way. Using the $^{13}$CO and C$^{18}$O $J = 1 - 0$ lines, and 850\,$μ$m continuum observations, we investigated cloud fragmentation and evolution associated with star formation. We extracted 468 clumps and 117 cores from the $^{13}$CO line and 850\,$μ$m continuum maps, respectively. We make use of the Bayesian Distance Calculator and derived the distanc…
We present a catalog of the 1525 most optically luminous galaxies from the Sloan Digital Sky Survey (SDSS) with r-band luminosity L_r > 8L* and redshift z<0.3, including 84 super spirals, 15 super lenticulars, 14 super post-merger galaxies, and 1400 giant ellipticals. With mass in stars of 10^{11.3}-10^{12} M_sun, super spirals and lenticulars are the most massive disk galaxies currently known. The specific star formation rates of super spirals place them on or below the star-forming main sequence. They must have formed stars at a high rate throughout their history in order to grow their massi…
The Neutral Hydrogen Gas Content of Star-forming and Quiescent S0 Galaxies
Universiti Malaya（马来亚大学）；Haverford College（哈弗福德学院）；Space Telescope Science Institute（太空望远镜科学研究所）；Johns Hopkins University（约翰斯·霍普金斯大学）；National Centre for Particle Physics, Universiti Malaya（马来亚大学国家粒子物理中心）
Brightest Cluster Galaxies (BCGs) residing in the centers of galaxy clusters are typically quenched giant ellipticals. A recent study hinted that star-forming galaxies with large disks, so-called superluminous spirals and lenticulars, are the BCGs of a subset of galaxy clusters. Based on the existing optical data it was not possible to constrain whether the superluminous disk galaxies reside at the center of galaxy clusters. In this work, we utilize XMM-Newton X-ray observations of five galaxy clusters to map the morphology of the intracluster medium (ICM), characterize the galaxy clusters, de…
As part of the VESTIGE survey, a blind narrow-band Ha+[NII] imaging survey of the Virgo cluster carried out with MegaCam at the CFHT, we discovered 8 massive lenticular galaxies with prominent ionised gas emission features in their inner (few kpc) regions. These features are either ionised gas filaments similar to those observed in cooling flows (2 gal), or thin discs with sizes 0.7<R(Ha)<2.0 kpc (6 gal), thus significantly smaller than those of the stellar disc. These discs have morphological properties similar to those of the dust seen in absorption in high-resolution HST images. Using a uni…
KAgoshima Galactic Object survey with Nobeyama 45-metre telescope by Mapping in Ammonia lines (KAGONMA): Discovery of parsec-scale CO depletion in the Canis Major star-forming region
The baryonic mass-size relation of galaxies. II. Implications for the evolutionary paths between star-forming and passive galaxies
Arcetri Astrophysical Observatory, INAF（阿切特里天文台，意大利国家天体物理研究所）；University of Science and Technology of China（中国科学技术大学）；Case Western Reserve University（凯斯西储大学）；University of Oregon（俄勒冈大学）
Based on the 850 $μ$m dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the $λ$ Orionis cloud to those of PGCCs in the Orion A and B clouds. The Orion A and B clouds are well known active star-forming regions, while the $λ$ Orionis cloud has a different environment as a consequence of the interaction with a prominent OB association and a giant Hii region. PGCCs in the $λ$ Orionis cloud have higher dust temperatures ($Td=16.13\pm0.15$ K) and lower values of dust emissivity spectral index ($ β=1.65\pm…
Very little work has been done on star formation in dwarf lenticular galaxies (S0s). We present 2D-spectroscopic and millimetre observations made by Centro Astronomico Hispano Aleman (CAHA) 3.5 m optical and the IRAM-30 m millimetre telescopes, respectively, for a sample of four dwarf S0 galaxies with multiple star formation regions in the field environment. We find that although most of the sources deviate from the star forming main sequence relation, they all follow the Kennicutt-Schmidt law. After comparing the stellar and Halpha kinematics, we find that the velocity fields of both stars an…
The origin of star-formation in customarily passively evolving early-type massive galaxies is poorly understood. We present a case study of a massive galaxy, I~Zw~81, inside the Bootes void. The void galaxy is known to host an active galactic nuclei (AGN). Our detailed 2D decomposition of the surface brightness distribution in the $Canada$ $France$ $Hawaii$ $Telescope$ ($CFHT$) g- and r-bands revealed multiple structural components such as a nuclear point source, a bar, a ring, and an inner exponential disk followed by an outer low surface brightness (LSB) disk. I~Zw~81 turns out to be a disk-…
Physically unassociated background or foreground objects seen towards submillimetre sources are potential contaminants of both the studies of young stellar objects embedded in Galactic dust clumps and multiwavelength counterparts of submillimetre galaxies (SMGs). We employed the near-infrared and mid-infrared data from the Wide-field Infrared Survey Explorer (WISE) and the submillimetre data from the Planck satellite, and uncovered a source, namely WISE J044232.92+322734.9, whose WISE infrared colours suggest that it is a star-forming galaxy (SFG), and which is seen in projection towards the P…
The lenticular galaxy IC 676 is a barred galaxy with double nuclei and active star formation in the central region. In this work we present the long-slit spectroscopy and archival multi-wavelength images to investigate the nature and origin of the double nuclei in IC 676. Through photometric 1D brightness profiles and 2D image decomposition, we show that this galaxy consists of a stellar bar with the length of $\sim$ 2.5 kpc and two Sérsic disks both of which with Sérsic index $\it n \sim$ 1.3. There is probably little or no bulge component assembled in IC 676. The luminosities of the double n…
Characterizing the Formation and Evolution of S0-galaxies (CaFES-0): Their formation pathways around Galaxy Clusters
Universidad Técnica Federico Santa María（费德里科·圣玛丽亚技术大学）；Millennium Nucleus for Galaxies (MINGAL)（银河系千年核心计划）；European Southern Observatory（欧洲南方天文台）；Universidad de La Serena（拉塞雷纳大学）；University of Nottingham（诺丁汉大学）；Laboratory of Astrophysics, Ecole Polytechnique Fédérale de Lausanne (EPFL)（洛桑联邦理工学院天体物理实验室）；Instituto de Estudios Astrofísicos, Facultad de Ingeniería y Ciencias, Universidad Diego Portales（迭戈·波特莱斯大学工程与科学学院天体物理研究所）；Universidade Federal do Rio de Janeiro（里约热内卢联邦大学）
In this paper we test if nearby blue spheroid (BSphs) galaxies may become the progenitors of star-forming spiral galaxies or passively-evolving elliptical galaxies. Our sample comprises 428 galaxies of various morphologies in the redshift range 0.002<z<0.02 (8-87 Mpc) with panchromatic data from the Galaxy and Mass Assembly survey. We find that BSph galaxies are structurally (mean effective surface brightness, effective radius) very similar to their passively-evolving red counterparts. However, their star-formation and other properties such as colour, age and metallicity are more like star-for…
Spectra that cover wavelengths from 0.6 to 1.1um are used to examine the behavior of emission and absorption features in a contiguous 22 x 300 arcsec region centered on the nearby dwarf galaxy NGC 55. Based on the relative strengths of various emission features measured over spatial scales of many tens of parsecs, it is concluded that the ionization states and sulphur abundances in most of the star-forming regions near the center of NGC 55 are similar. A large star-forming region is identified in the north west part of the disk at a projected distance of ~1 kpc from the galaxy center that has …
We use comparisons between the SAMI Galaxy Survey and equilibrium galaxy models to infer the importance of disc fading in the transition of spirals into lenticular (S0) galaxies. The local S0 population has both higher photometric concentration and lower stellar spin than spiral galaxies of comparable mass and we test whether this separation can be accounted for by passive aging alone. We construct a suite of dynamically self--consistent galaxy models, with a bulge, disc and halo using the GalactICS code. The dispersion-dominated bulge is given a uniformly old stellar population, while the dis…
Old Disks Die Hard: How Does AGN Feedback Suppress Disk Formation in Milky Way Mass Galaxies?
University of California Irvine（加州大学尔湾分校）；University of Southern California（南加州大学）；Wesleyan University（卫斯理安大学）；Pomona College（波莫纳学院）；University of California Davis（加州大学戴维斯分校）
Unveiling a cosmic tango: Integral field spectroscopy and numerical simulations of Arp 143's interaction
Université Laval（拉瓦尔大学）；Universidad de Granada（格拉纳达大学）；Instituto de Astrofísica de Andalucía, CSIC（安达卢西亚天体物理学研究所，西班牙国家研究委员会）；Centro Astronómico Hispano en Andalucía, Observatorio de Calar Alto（西班牙-安达卢西亚天文中心，卡拉萨罗天文台）
The lenticular galaxy NGC474 hosts a rich system of tidal shells and streams, some of which are exceptionally bright. Two teams recently presented spectroscopic observations of the brightest shells. These were the first shell spectra ever observed in integrated starlight. The authors studied the stellar populations of the shell, of the center of the galaxy and of its globular clusters. The precise formation scenario for the tidal features of this prominent galaxy however still remained unclear. Here, we add further clues on their formation from the radii of the shells, and we present a scenari…
Scaling Relations across Galaxy Classification Schemes: I. Star Formation Rate-Stellar Mass Plane of CALIFA Nearby Galaxies
Max Planck Institute for Radio Astronomy（马克斯·普朗克射电天文研究所）；Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences（保加利亚科学院天体物理与国立天文台）；National Astronomical Observatory of Japan（日本国立天文台）；SOKENDAI（综合研究大学院大学）；Argelander-Institut für Astronomie, University of Bonn（波恩大学阿尔坎德天文研究所）
Using multi-band data we examine the star formation activity of the nearby group-dominant early-type galaxies of the Complete Local-volume Groups Sample (CLoGS), and the relation between star formation, gas content, and local environment. Only a small fraction of the galaxies (13%; 6/47) are found to be Far-Ultraviolet (FUV) bright, with FUV to near-infrared colours indicative of recent active star formation (NGC 252, NGC 924, NGC 940, NGC 1106, NGC 7252, and ESO 507-25). These systems are lenticulars presenting the highest FUV specific star-formation rates in the sample (sSFR FUV > 5$\times$1…
From blue to red spirals: Slow galaxy transformation via ram pressure stripping in TNG-50
Instituto de Ciencias Nucleares (UNAM)（墨西哥国立自治大学核科学研究所）；Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg（海德堡大学天文学计算研究所）；INAF - Padova Astronomical Observatory（意大利国家天体物理研究所帕多瓦天文台）；Instituto de Radioastronomía y Astrofísica (UNAM)（墨西哥国立自治大学射电天文学与天体物理学研究所）；Instituto de Astronomía (UNAM)（墨西哥国立自治大学天文学研究所）
