- ID:
- ivo://CDS.VizieR/J/ApJS/157/175
- Title:
- DEEP Groth Strip Survey. VIII.
- Short Name:
- J/ApJS/157/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a candidate sample of luminous bulges (including ellipticals) found within the Groth Strip Survey (GSS), with spectroscopic redshifts of 0.73<z<1.04 from the Keck Telescope. This work is distinguished by its use of two-dimensional two-component decomposition photometry from Hubble Space Telescope (HST) images to separate the bulge from any disk before applying the sample selection and to measure disk-free colors. We define a statistically complete sample of 86 bulges with r^1/4^ profiles and luminosities brighter than I_AB_=24. Although larger samples of distant early-type galaxies exist, this is the largest and most homogeneous sample of bulges at z~1 with spectroscopy. A brighter subset of 52 objects with added structural constraints defines our "quality sample" that is used to explore bulge luminosities and colors.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/571/136
- Title:
- DEEP Groth Strip survey. X.
- Short Name:
- J/ApJ/571/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the luminosity function and color-redshift relation of a magnitude-limited sample of 145 mostly red field E/S0 galaxies at z<~1 from the DEEP Groth Strip Survey (GSS). Using nearby galaxy images as a training set, we develop a quantitative method to classify E/S0 galaxies based on smoothness, symmetry, and bulge-to-total light ratio. Using this method, we identify 145 E/S0's at 16.5<I<22 within the GSS, for which 44 spectroscopic redshifts (z_spec_) are available. Most of the galaxies with spectroscopic redshifts (86%) form a "red envelope" in the redshift-color diagram, consistent with predictions of spectral synthesis models in which the dominant stellar population is formed at redshifts z>~1.5.
- ID:
- ivo://CDS.VizieR/J/A+A/591/A117
- Title:
- Deep Herschel PACS point spread functions
- Short Name:
- J/A+A/591/A117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The knowledge of the point spread function (PSF) of imaging instruments represents a fundamental requirement for astronomical observations. The Herschel PACS PSFs delivered by the instrument control centre are obtained from observations of the Vesta asteroid, providing a characterisation of the central part therefore excluding fainter features. However, inumany cases information on both the core and the wings of the PSFs is needed. With this aim, we combine Vesta and Mars dedicated observations and obtain PACS PSFs with an unprecedented dynamic range (~10^6^), at slow and fast scan speeds and for the three photometric bands.
- ID:
- ivo://CDS.VizieR/J/ApJS/150/417
- Title:
- Deep, high-resolution survey at 74MHz
- Short Name:
- J/ApJS/150/417
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a 74MHz survey of a 165deg^2^ region located near the north Galactic pole. This survey has an unprecedented combination of both resolution (25" FWHM) and sensitivity ({sigma} as low as 24mJy/beam). We detect 949 sources at the 5{sigma} level in this region, enough to begin exploring the nature of the 74MHz source population. We present differential source counts, spectral index measurements, and the size distribution as determined from counterparts in the high-resolution FIRST 1.4GHz survey, Cat. <VIII/71>.
- ID:
- ivo://CDS.VizieR/J/A+A/612/A26
- Title:
- Deep HI observations of Leo T with WSRT
- Short Name:
- J/A+A/612/A26
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Leo T is the lowest mass gas-rich galaxy currently known and studies of its gas content help us understand how such marginal galaxies survive and form stars. We present deep neutral hydrogen (HI) observations from the Westerbork Synthesis Radio Telescope in order to understand its HI distribution and potential for star formation. We find a larger HI line flux than the previously accepted value, resulting in a 50% larger HI mass of 4.1x10^5^M_{sun}_. The additional HI flux is from low surface brightness emission that was previously missed; with careful masking this emission can be recovered even in shallower data.We perform a Gaussian spectral decomposition to find a cool neutral medium component (CNM) with a mass of 3.7x10^4^M_{sun}_, or almost 10% of the total HI mass. Leo T has no HI emission extending from the main HI body, but there is evidence of interaction with the Milky Way circumgalactic medium in both a potential truncation of the HI body and the offset of the peak HI distribution from the optical center. The CNM component of Leo T is large when compared to other dwarf galaxies, even though Leo T is not currently forming stars and has a lower star formation efficiency than other gas-rich dwarf galaxies. However, the HI column density associated with the CNM component in Leo T is low. One possible explanation is the large CNM component is not related to star formation potential but rather a recent, transient phenomenon related to the interaction of Leo T with the Milky Way circumgalactic medium.
- ID:
- ivo://CDS.VizieR/J/ApJ/743/64
- Title:
- Deep infrared photometry of {sigma} Ori cluster
- Short Name:
- J/ApJ/743/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep I, Z photometric survey covering a total area of 1.12deg^2^ of the {sigma} Orionis cluster and reaching completeness magnitudes of I=22 and Z=21.5mag. From I, I-Z color-magnitude diagrams we have selected 153 candidates that fit the previously known sequence of the cluster. They have magnitudes in the range I=16-23mag, which corresponds to a mass interval from 0.1 down to 0.008M_{sun}_ at the most probable age of {sigma} Orionis (2-4Myr). Using J-band photometry, we find that 124 of the 151 candidates within the completeness of the optical survey (82%) follow the previously known infrared photometric sequence of the cluster and are probably members. We have studied the spatial distribution of the very low mass stars and brown dwarf population of the cluster and found that there are objects located at distances greater than 30 arcmin to the north and west of {sigma} Orionis that probably belong to different populations of the Orion's Belt. For the 102 bona fide {sigma} Orionis cluster member candidates, we find that the radial surface density can be represented by a decreasing exponential function ({sigma}={sigma}_0_e^-r/r_0_^) with a central density of {sigma}_0_=0.23+/-0.03 objects arcmin^-2^ and a characteristic radius of r_0_=9.5+/-0.7 arcmin. Using near-infrared JHK-band data from Two Micron All Sky Survey and UKIRT Deep Infrared Sky Survey and mid-infrared data from Infrared Array Camera/Spitzer, we find that about 5%-9% of the brown dwarf candidates in the {sigma} Orionis cluster have K-band excesses and 30%+/-7% of them show mid-infrared excesses at wavelengths longer than 5.8um. These are probably related to the presence of disks, most of which are "transition disks".
- ID:
- ivo://CDS.VizieR/J/ApJS/235/34
- Title:
- Deep JVLA imaging of GOODS-N at 20cm
- Short Name:
- J/ApJS/235/34
- Date:
- 08 Mar 2022 13:27:20
- Publisher:
- CDS
- Description:
- New wideband continuum observations in the 1-2GHz band of the GOODS-N field using NSF's Karl G. Jansky Very Large Array (VLA) are presented. The best image with an effective frequency of 1525MHz reaches an rms noise in the field center of 2.2{mu}Jy, with 1.6" resolution. A catalog of 795 sources is presented covering a radius of 9 arcminutes centered near the nominal center for the GOODS-N field, very near the nominal VLA pointing center for the observations. Optical/NIR identifications and redshift estimates both from ground-based and HST observations are discussed. Using these optical/NIR data, it is most likely that fewer than 2% of the sources without confusion problems do not have a correct identification. A large subset of the detected sources have radio sizes >1". It is shown that the radio orientations for such sources correlate well with the HST source orientations, especially for z<1. This suggests that a least a large subset of the 10kpc-scale disks of luminous infrared/ultraluminous infrared galaxies (LIRG/ULIRG) have strong star formation, not just in the nucleus. For the half of the objects with z>1, the sample must be some mixture of very high star formation rates, typically 300M_{sun}_/yr, assuming pure star formation, and an active galactic nucleus (AGN) or a mixed AGN/star formation population.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4578
- Title:
- Deep learning classification in asteroseismology
- Short Name:
- J/MNRAS/469/4578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a 1D convolutional neural network by supervised learning to automatically learn these visual features from images of folded oscillation spectra. By training and testing on Kepler red giants, we achieve an accuracy of up to 99 per cent in separating helium-burning red giants from those ascending the red giant branch. The convolutional neural network additionally shows capability in accurately predicting the evolutionary states of 5379 previously unclassified Kepler red giants, by which we now have greatly increased the number of classified stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/863/25
- Title:
- Deep Magellan/Megacam obs. of 4 MW satellites
- Short Name:
- J/ApJ/863/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep Magellan/Megacam stellar photometry of four recently discovered faint Milky Way satellites: Sagittarius II (Sgr II), Reticulum II (Ret II), Phoenix II (Phe II), and Tucana III (Tuc III). Our photometry reaches ~2-3 magnitudes deeper than the discovery data, allowing us to revisit the properties of these new objects (e.g., distance, structural properties, luminosity measurements, and signs of tidal disturbance). The satellite color-magnitude diagrams show that they are all old (~13.5Gyr) and metal poor ([Fe/H]<~-2.2). Sgr II is particularly interesting, as it sits in an intermediate position between the loci of dwarf galaxies and globular clusters in the size-luminosity plane. The ensemble of its structural parameters is more consistent with a globular cluster classification, indicating that Sgr II is the most extended globular cluster in its luminosity range. The other three satellites land directly on the locus defined by Milky Way ultra-faint dwarf galaxies of similar luminosity. Ret II is the most elongated nearby dwarf galaxy currently known for its luminosity range. Our structural parameters for Phe II and Tuc III suggest that they are both dwarf galaxies. Tuc III is known to be associated with a stellar stream, which is clearly visible in our matched-filter stellar density map. The other satellites do not show any clear evidence of tidal stripping in the form of extensions or distortions. Finally, we also use archival HI data to place limits on the gas content of each object.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1384
- Title:
- Deep MERLIN 5GHz radio sources in M82
- Short Name:
- J/MNRAS/391/1384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of an extremely deep, 8-d long observation of the central kpc of the nearby starburst galaxy M82 using Multi-Element Radio Linked Interferometer Network (MERLIN) at 5GHz are presented. The 17{mu}Jy/beam rms noise level in the naturally weighted image makes it the most sensitive high-resolution radio image of M82 made to date. Over 50 discrete sources are detected, the majority of which are supernova remnants, but with 13 identified as H ii regions. Sizes, flux densities and radio brightnesses are given for all of the detected sources, which are all well resolved with a majority showing shell or partial shell structures. Those sources within the sample which are supernova remnants have diameters ranging from 0.3 to 6.7pc, with a mean size of 2.9pc.