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تسجيل مستخدم جديدThe H$alpha$ Dots Survey. IV. A Fourth List of Faint Emission-Line Objects
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We present the fourth catalog of serendipitously discovered compact extragalactic emission-line sources -- H$alpha$ Dots. A total of 454 newly discovered objects are included in the current survey list. These objects have been detected in searches of moderately deep narrow-band images acquired for the ALFALFA H$alpha$ project (Van Sistine et al. 2016). The catalog of H-alpha Dots presented in the current paper was derived from searches carried out using ALFALFA H$alpha$ images obtained with the KPNO 2.1 m telescope. This results in a substantially deeper sample of Dots compared to our previous lists, which were all discovered in images taken with the WIYN 0.9 m telescope. The median R-band magnitude of the current catalog is 21.59, more than 1.6 magnitudes fainter than the median for the 0.9~m sample (factor of 4.4x fainter). Likewise, the median emission-line flux of the detected sources is a factor of 4.3x fainter. The line-flux completeness limit of the current sample is approximately 3 x 10$^{-16}$ erg/s/cm$^2$. We present accurate coordinates, apparent magnitudes and narrow-band line fluxes for each object in the sample. Unlike our previous lists of H$alpha$ Dots, the current sample does not include follow-up spectroscopy.
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We present the second catalog of serendipitously discovered compact extragalactic emission-line sources -- H$alpha$ Dots. These objects have been discovered in searches of moderately deep narrow-band images acquired for the ALFALFA H$alpha$ project (
Van Sistine et al. 2016). In addition to cataloging 119 new H$alpha$ Dots, we also present follow-up spectral data for the full sample. These spectra allow us to confirm the nature of these objects as true extragalactic emission-line objects, to classify them in terms of activity type (star forming or AGN), and to identify the emission line via which they were discovered. We tabulate photometric and spectroscopic data for the all objects, and present an overview of the properties of the full H$alpha$ Dot sample. The H$alpha$ Dots represent a broad range of star-forming and active galaxies detected via several different emission lines over a wide range of redshifts. The sample includes H$alpha$-detected blue compact dwarf galaxies at low redshift, [ion{O}{3}]-detected Seyfert 2 and Green Pea-like galaxies at intermediate redshifts, and QSOs detected via one of several UV emission lines, including Ly$alpha$. Despite the heterogeneous appearance of the resulting catalog of objects, we show that our selection method leads to well-defined samples of specific classes of emission-line objects with properties that allow for statistical studies of each class.
We present the fourth list with results of the Hamburg/SAO Survey for Emission-Line Galaxies (HSS hereafter, SAO - Special Astrophysical Observatory, Russia). The list is a result of the follow-up spectroscopy conducted with the 6m SAO RAS telescope
in 1998, 1999 and 2000. The data of this snap-shot spectroscopy survey confirmed 127 emission-line objects out of 176 observed candidates and allowed their quantitative spectral classification. We could classify 76 emission-line objects as BCG/HII galaxies or probable BCGs, 8 - as QSOs, 2 - as Seyfert galaxies, 2 - as super-associations in a subluminous spiral and an irregular galaxy, and 37 as low-excitation objects - either starburst nuclei (SBN), or dwarf amorphous nuclei starburst galaxies (DANS). We could not classify 2 ELGs. Furthermore, for 5 galaxies we did not detect any significant emission lines. For 91 emission-line galaxies, the redshifts and/or line intensities are determined for the first time. Of the remaining 28 previously known ELGs we give either improved data on the line intensities or some independent measurements. The candidates were taken from three different samples selected by different criteria. Among our first priority candidates we achieved a detection rate of emission-line objects (ELGs + QSOs) of 68%, among which 51% are BCGs. Observations of a random selected sample among our second priority candidates showed that only ~10% are BCGs. We found that the confirmed BCGs have usually a blue colour ((B-R) < 1.0) and a non-stellar appearance in the APM database. Our third sample is comprised of second priority candidates fulfilling these criteria derived from the APM. Follow-up spectroscopy of a small subsample indicates that the expected detection rate for BCGs is ~40%.
The KPNO International Spectroscopic Survey (KISS) is an objective-prism survey for extragalactic emission-line objects. It combines many of the features of previous slitless spectroscopic surveys with the advantages of modern CCD detectors, and is t
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We present a catalogue of candidate H{alpha} emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (l x b) = (6 x 1) degrees centred at b = 1.
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