Near-infrared observations of ionized hydrogen at the core of the Galaxy

1979 ◽  
Vol 229 ◽  
pp. 917 ◽  
Author(s):  
J. Bally ◽  
N. Z. Scoville ◽  
R. R. Joyce
Keyword(s):  
Near Infrared ◽  
Infrared Observations ◽  
The Core ◽  
The Galaxy

scholarly journals Optical and near-infrared observations of the SPT2349-56 proto-cluster core at z = 4.3

2021 ◽  
Vol 502 (2) ◽  
pp. 1797-1815
Author(s):  
K M Rotermund ◽  
S C Chapman ◽  
K A Phadke ◽  
R Hill ◽  
E Pass ◽  
...  
Keyword(s):  
Near Infrared ◽  
Early Stage ◽  
Stellar Mass ◽  
Cluster Core ◽  
Cluster Galaxy ◽  
Infrared Observations ◽  
The Core ◽  
Virial Mass ◽  
Stellar Masses ◽  
Optical Surveys

ABSTRACT We present Gemini-S and Spitzer-IRAC optical-through-near-IR observations in the field of the SPT2349-56 proto-cluster at z = 4.3. We detect optical/IR counterparts for only 9 of the 14 submillimetre galaxies (SMGs) previously identified by ALMA in the core of SPT2349-56. In addition, we detect four z ∼ 4 Lyman-break galaxies (LBGs) in the 30 arcsec-diameter region surrounding this proto-cluster core. Three of the four LBGs are new systems, while one appears to be a counterpart of one of the nine observed SMGs. We identify a candidate brightest cluster galaxy (BCG) with a stellar mass of $(3.2^{+2.3}_{-1.4})\times 10^{11}$ M⊙. The stellar masses of the eight other SMGs place them on, above, and below the main sequence of star formation at z ≈ 4.5. The cumulative stellar mass for the SPT2349-56 core is at least (12.2 ± 2.8) × 1011 M⊙, a sizeable fraction of the stellar mass in local BCGs, and close to the universal baryon fraction (0.19) relative to the virial mass of the core (1013 M⊙). As all 14 of these SMGs are destined to quickly merge, we conclude that the proto-cluster core has already developed a significant stellar mass at this early stage, comparable to z = 1 BCGs. Importantly, we also find that the SPT2349-56 core structure would be difficult to uncover in optical surveys, with none of the ALMA sources being easily identifiable or constrained through g, r, and i colour selection in deep optical surveys and only a modest overdensity of LBGs over the more extended structure. SPT2349-56 therefore represents a truly dust-obscured phase of a massive cluster core under formation.

scholarly journals The Luminosity of the Central Parsec of the Galaxy

1989 ◽  
Vol 136 ◽  
pp. 423-436
Author(s):  
M. W. Werner ◽  
J. A. Davidson
Keyword(s):  
Near Infrared ◽  
Galactic Center ◽  
Thermal Emission ◽  
Large Magellanic Cloud ◽  
Infrared Emission ◽  
Infrared Observations ◽  
The Galaxy ◽  
Infrared Wavelengths ◽  
Central Parsec ◽  
30 Doradus

The luminosity of the central 5 pc of the Galaxy -encompassing the inner regions of the rotating ring of dust and gas which surrounds the galactic center - emerges primarily at infrared wavelengths in the form of thermal emission from heated dust. The nature and location of the sources which heat the dust can be inferred from the spatial and temperature distribution of the thermal infrared emission (λ>20um), from studies of the ionized gas in this region, and from direct imaging in the near infrared. These observations show that the principal heating sources within this 5-pc region are concentrated within the central parsec of the Galaxy and indicate that the luminosity of these sources is within a factor of two of 107 LO. The near-infrared observations of the compact sources at the galactic center do not reveal a single dominant source but suggest instead that the several components of the IRS-16 complex, taken together, may contribute the bulk of the luminosity; however, the data also permit a single object to dominate the energetics of this region. We draw attention to the striking morphological similarities between the galactic center and the innermost regions of the 30 Doradus nebula in the Large Magellanic Cloud and speculate that the luminosity sources in the galactic center may resemble the early-type supergiants in 30 Doradus.

scholarly journals UV spectroscopy confirms SU Lyn to be a symbiotic star

2020 ◽  
Vol 500 (1) ◽  
pp. L12-L16
Author(s):  
Vipin Kumar ◽  
Mudit K Srivastava ◽  
Dipankar P K Banerjee ◽  
Vishal Joshi
Keyword(s):  
Near Infrared ◽  
Uv Spectroscopy ◽  
Symbiotic Star ◽  
Symbiotic Stars ◽  
High Excitation ◽  
Uv Spectrum ◽  
Infrared Observations ◽  
X Ray ◽  
The Galaxy ◽  
Type Giant

ABSTRACT SU Lyn, a star that ostensibly appears to be an unremarkable late M type giant, has recently been proposed to be a symbiotic star largely based on its hard X-ray properties. The star does not display, in low-resolution optical spectra, the high excitation lines typically seen in the spectra of symbiotic stars. In this work, ultraviolet (UV), optical, and near-infrared observations are presented, aimed at exploring and strengthening the proposed symbiotic classification for this star. Our far-UV 1300–1800 Å spectrum of SU Lyn, obtained with the ASTROSAT mission’s UVIT payload, shows emission lines of Si iv, C iv, O iii, and N iii in a spectrum typical of symbiotic stars. The UV spectrum robustly confirms SU Lyn’s symbiotic nature. The detection of high excitation lines in a high-resolution optical spectrum further consolidates its symbiotic nature. As is being recognized, the potential existence of other similar symbiotic systems could significantly impact the census of symbiotic stars in the Galaxy.

scholarly journals Deep Near‐Infrared Observations of L1014: Revealing the Nature of the Core and Its Embedded Source

2006 ◽  
Vol 640 (1) ◽  
pp. 391-401 ◽  
Author(s):  
Tracy L. Huard ◽  
Philip C. Myers ◽  
David C. Murphy ◽  
Lionel J. Crews ◽  
Charles J. Lada ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Observations ◽  
The Core

scholarly journals A near-infrared study of the obscured 3C129 galaxy cluster

2020 ◽  
Vol 644 ◽  
pp. A107
Author(s):  
M. Ramatsoku ◽  
M. A. W. Verheijen ◽  
R. C. Kraan-Korteweg ◽  
T. H. Jarrett ◽  
K. Said ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Plane ◽  
Galaxy Cluster ◽  
Imaging Data ◽  
Infrared Study ◽  
X Ray ◽  
Cluster Galaxies ◽  
The Core ◽  
Main Cluster ◽  
The Galaxy

We present a catalogue of 261 new infrared selected members of the 3C 129 galaxy cluster. The cluster, located at z ≈ 0.02, forms part of the Perseus-Pisces filament and is obscured at optical wavelengths due to its location in the zone of avoidance. We identified these galaxies using the J- and K-band imaging data provided by the UKIDSS Galactic Plane Survey within an area with a radius of 1.1° centred on the X-ray emission of the cluster at ℓ, b ≈ 160.52° ,0.27°. A total of 26 of the identified galaxy members have known redshifts 24 of which are from our 2016 Westerbork H I survey and two are from optical spectroscopy. An analysis of the galaxy density at the core of the 3C 129 cluster shows it to be less dense than the Coma and Norma clusters, but comparable to the galaxy density in the core of the Perseus cluster. From an assessment of the spatial and velocity distributions of the 3C 129 cluster galaxies that have redshifts, we derived a velocity of cz = 5227 ± 171 km s−1 and σ = 1097 ± 252 km s−1 for the main cluster, with a substructure in the cluster outskirts at cz = 6923 ± 71 km s−1 with σ = 422 ± 100 km s−1. The presence of this substructure is consistent with previous claims based on the X-ray analysis that the cluster is not yet virialised and may have undergone a recent merger.

scholarly journals Near-infrared studies of the Milky Way

1985 ◽  
Vol 106 ◽  
pp. 123-126 ◽  
Author(s):  
H. Okuda
Keyword(s):  
Near Infrared ◽  
Milky Way ◽  
Field Configuration ◽  
Magnetic Field Configuration ◽  
Infrared Observations ◽  
Infrared Studies ◽  
The Galaxy ◽  
Inner Region ◽  
The Magnetic Field ◽  
Infrared Brightness

The inner region of the Galaxy has been explored by means of near-infrared observations; the distribution and population of the stars are studied from the near-infrared brightness mapping and star counts in the Milky Way, while the magnetic-field configuration is probed by the near-infrared polarimetry.

scholarly journals The OH/IR star population at the centre of the Galaxy

2002 ◽  
Vol 206 ◽  
pp. 335-338
Author(s):  
Roberto Ortiz ◽  
Alain Omont ◽  
Mathias Schultheis ◽  
Eric Copet ◽  
Harm J. Habing ◽  
...  
Keyword(s):  
Near Infrared ◽  
Galactic Plane ◽  
High Spatial Resolution ◽  
Agb Stars ◽  
Mid Infrared ◽  
Infrared Observations ◽  
Ir Stars ◽  
The Galaxy ◽  
Bulge Region ◽  
Infrared Data

In the last years various OH surveys at 1612 MHz have been carried out in the galactic bulge region with high spatial resolution (Lindqvist et al. 1992; Sevenster et al. 1997; Sjouwerman et al. 1998) which have resulted in the detection of over five hundred double-peaked objects commonly associated with oxygen-rich AGB stars. More recently, the ISOGAL survey, which is part of the ISO mission, scanned several regions along the galactic plane, including the inner bulge, at 6.8 and 15 micron wavelengths. In this work we report an analysis of 104 OH/IR stars in the bulge, based on near and mid-infrared observations. Mass-loss rates, luminosities and masses are determined for a sub-sample of stars, for which near-infrared data are available in the literature.

scholarly journals Lyman break galaxies at z>6

2006 ◽  
Vol 2 (14) ◽  
pp. 246-246
Author(s):  
Rychard J. Bouwens ◽  
Garth D. Illingworth
Keyword(s):  
Strong Evidence ◽  
Rest Frame ◽  
Near Infrared ◽  
Direct Result ◽  
Infrared Observations ◽  
Star Forming ◽  
Lyman Break Galaxies ◽  
The Galaxy ◽  
Galaxy Population

AbstractExtending the study of star-forming galaxies to z>6 is extremely difficult due to the faintness of the sources and the challenging nature of deep near-infrared observations. Nevertheless, current observations are now just good enough that we can begin drawing some conclusions about the nature of galaxies at z≳7. At present, deep near-infrared observations with NICMOS (reaching ≳27 AB mag at 5σ) cover more than 20arcmin2 of area with deep optical coverage and allow us to identify four strong z≃7–8 candidates. Comparing this sample with dropout samples at later times (z≃4–6), we are able to study evolution in the rest-frame UV LF over the range z≃8 to z≃4. We find strong evidence for significant evolution in the characteristic luminosity with time (brightening by ∼2 mag, from z≃8 to z≃4). The observed evolution appears to be the direct result of hierarchical growth in the galaxy population.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals High-contrast and resolution near-infrared photometry of the core of R136

2021 ◽  
Vol 503 (1) ◽  
pp. 292-311
Author(s):  
Zeinab Khorrami ◽  
Maud Langlois ◽  
Paul C Clark ◽  
Farrokh Vakili ◽  
Anne S M Buckner ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Outer Region ◽  
Mass Range ◽  
Mass Function ◽  
Large Magellanic Cloud ◽  
Star Forming ◽  
The Core ◽  
Very Large Telescope ◽  
30 Doradus

ABSTRACT We present the sharpest and deepest near-infrared photometric analysis of the core of R136, a newly formed massive star cluster at the centre of the 30 Doradus star-forming region in the Large Magellanic Cloud. We used the extreme adaptive optics of the SPHERE focal instrument implemented on the ESO Very Large Telescope and operated in its IRDIS imaging mode for the second time with longer exposure time in the H and K filters. Our aim was to (i) increase the number of resolved sources in the core of R136, and (ii) to compare with the first epoch to classify the properties of the detected common sources between the two epochs. Within the field of view (FOV) of 10.8″ × 12.1″ ($2.7\,\text {pc}\times 3.0\, \text {pc}$), we detected 1499 sources in both H and K filters, for which 76 per cent of these sources have visual companions closer than 0.2″. The larger number of detected sources enabled us to better sample the mass function (MF). The MF slopes are estimated at ages of 1, 1.5, and 2 Myr, at different radii, and for different mass ranges. The MF slopes for the mass range of 10–300 M⊙ are about 0.3 dex steeper than the mass range of 3–300 M⊙, for the whole FOV and different radii. Comparing the JHK colours of 790 sources common in between the two epochs, 67 per cent of detected sources in the outer region (r > 3″) are not consistent with evolutionary models at 1–2 Myr and with extinctions similar to the average cluster value, suggesting an origin from ongoing star formation within 30 Doradus, unrelated to R136.

Sign in / Sign up

Export Citation Format

Share Document