- ID:
- ivo://CDS.VizieR/J/AN/324/437
- Title:
- H{alpha} emission stars toward Bulge
- Short Name:
- J/AN/324/437
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is dealing with the investigation of H-alpha emission stars towards the galactic bulge. In this important region 533 H-alpha emission stars have already been discovered. We add 98 new and 9 possible new (perhaps identical with known objects) H-alpha emission stars found in the objective-prism survey of planetary nebulae and we give the identification charts, the accurate coordinates as well as a rough description. The distribution in l, b of all objects shows the expected concentration towards the galactic equator with the maximum near l=0 and b=0 distorted probably due to strong interstellar extinction.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/2041
- Title:
- H{alpha} emitters at z=2.23
- Short Name:
- J/MNRAS/416/2041
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a narrow-band (H_2_S1, {lambda}_c_=2.121um, {delta}{lambda}=0.021um) imaging search with Wide Field Camera/United Kingdom Infrared Telescope for H{alpha} emitters (HAEs) around several potential signposts of rare (~10^-7^-10^-8^ comoving Mpc^-3^) overdense regions at z=2.23: an overdensity of quasi-stellar objects [QSOs; 2dF QSO Redshift Survey (2QZ) cluster], a powerful, high-redshift radio galaxy (HzRG) and a concentration of submillimetre galaxies (SMGs) and optically faint radio galaxies (OFRGs). In total, we detect 137 narrow-band emitter candidates down to emission-line fluxes of 0.5-1x10^-16^erg/s/cm^2^, across a total area of 0.56deg^2^ (2.1x10^5^ comoving Mpc^3^ at z=2.23) in these fields.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1977
- Title:
- H-alpha emitters in/towards USS 1558
- Short Name:
- J/MNRAS/473/1977
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out deep H{alpha} narrowband imaging with 10h net integrations towards the young protocluster, USS1558-003 at z=2.53 with the Subaru Telescope. This system is composed of four dense groups with massive local overdensities, traced by 107 H{alpha} emitters (HAEs) with stellar masses and dust-corrected star formation rates down to 1x10^8^M_{sun}_ and 3M_{sun}_/yr, respectively. We have investigated the environmental dependence of various physical properties within the protocluster by comparing distributions of HAEs in higher and lower densities with a standard Kolmogorov-Smirnov test. At 97 per cent confidence level, we find enhanced star formation across the star-forming main sequence of HAEs living in the most extreme 'supergroup', corresponding to the top quartile of overdensities. Furthermore, we derive distribution functions of H{alpha} luminosity and stellar mass in group and intergroup regions, approximately corresponding to 30 and 8 times higher densities than the general field. As a consequence, we identify 0.7 and 0.9dex higher cut-offs in H{alpha} luminosity and stellar mass functions in the dense groups, respectively. On the other hand, HAEs in the intergroup environment of the protocluster show similar distribution functions to those of field galaxies despite residing in significant overdensities. In the early phase of cluster formation, as inferred from our results, the densest parts in the protocluster have had an accelerated formation of massive galaxies. We expect that these eventually grow and transform into early-type galaxies at the bright end of the red sequence as seen in present-day rich clusters of galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJS/175/128
- Title:
- H{alpha} emitting galaxies in COSMOS-2 field
- Short Name:
- J/ApJS/175/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To derive a new H{alpha} luminosity function and to understand the clustering properties of star-forming galaxies at z~0.24, we have made a narrowband imaging survey for H{alpha}-emitting galaxies in the Hubble Space Telescope (HST) COSMOS 2 square degree field. We used the narrowband filter NB816 ({lambda}_c_=8150{AA}, {Delta}{lambda}=120{AA}) and sampled H{alpha} emitters with EW_obs_(H{alpha}+[NII])>12{AA} in a redshift range between z=0.233 and 0.251 corresponding to a depth of 70Mpc. We obtained 980 H{alpha}-emitting galaxies in a sky area of 5540arcmin^2^, corresponding to a survey volume of 3.1x10^4^Mpc^3^.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2739
- Title:
- H-alpha emitting regions in M33
- Short Name:
- J/AJ/110/2739
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report finding charts and accurate positions for 432 compact H{alpha} emitting regions in the Local Group Galaxy M33 (NGC 598), in an effort to isolate candidates for an SS433-like stellar system. The objects were extracted from narrowband images, centered in the rest frame H{alpha} ({lambda}6563A) and in the red continuum at 6100A. The atlas is complete down to V=~20, and includes 279 compact H II regions and 153 line emitting point-like sources. The point-like sources undoubtedly include a variety of objects: very small H II regions, early type stars with intense stellar winds, and Wolf-Rayet stars, but should also contain objects with the characteristics of SS433. This extensive survey of compact H{alpha} regions in M33 is a first step towards the identification of peculiar stellar systems like SS433 in external galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/613/L5
- Title:
- H{alpha} emitting sources around MWC758
- Short Name:
- J/A+A/613/L5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- MWC758 is a young star surrounded by a transitional disk. The disk shows an inner cavity and spiral arms that could be caused by the presence of protoplanets. Recently, a protoplanet candidate has been detected around MWC758 through high-resolution L'-band observations. The candidate is located inside the disk cavity at a separation of 111 mas from the central star, and at an average position angle of 165.5{deg}. We aim at detecting accreting protoplanet candidates within the disk of MWC758 through spectral angular differential imaging observations in the optical regime. In particular, we explore the emission at the position of the detected planet candidate. We have performed simultaneous adaptive optics observations in the H{alpha} line and the adjacent continuum using SPHERE/ZIMPOL at the Very Large Telescope (VLT). The data analysis does not reveal any H{alpha} signal around the target. The derived contrast curve in the B_Ha filter allows us to derive a 5{sigma} upper limit of 7.6mag at 111mas, the separation of the previously detected planet candidate. This contrast translates into a H{alpha} line luminosity of LH{alpha}<~5*10^-5^L_{sun}_ at 111mas. Assuming that LH{alpha} scales with Lacc as in Classical T Tauri stars as a first approximation, we can estimate an accretion luminosity of Lacc<3.7*10^-4^L_{sun}_ for the protoplanet candidate. For the predicted mass range of MWC758b, 0.5-5M_Jup_, this implies accretion rates smaller than dM/dt<3.4*(10^-8^-10^-9^)M_[sun}_/yr, for an average planet radius of 1.1 RJup. Therefore, our estimates are consistent with the predictions of accreting circumplanetary accretion models for R_in_=1R_Jup_. The ZIMPOL line luminosity is consistent with the H{alpha} upper limit predicted by these models for truncation radii <~3.2R_Jup_. The non-detection of any H{alpha}emitting source in the ZIMPOL images does not allow us to unveil the nature of the L' detected source. Either it is a protoplanet candidate or a disk asymmetry.
- ID:
- ivo://CDS.VizieR/J/A+A/458/569
- Title:
- H{alpha} equivalent widths of 36 Lyn (HD 79158)
- Short Name:
- J/A+A/458/569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper reports the photospheric, magnetic and circumstellar gas characteristics of the magnetic B8p star 36 Lyncis (HD 79158). Using archival data and new polarised and unpolarised high-resolution spectra, we redetermine the basic physical properties, the rotational period and the geometry of the magnetic field, and the photospheric abundances of various elements.
- ID:
- ivo://CDS.VizieR/J/ApJ/604/141
- Title:
- H{alpha} fluxes in Cl J0023+0423B galaxies
- Short Name:
- J/ApJ/604/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present H{alpha}-derived star formation rates (SFRs) for the galaxy cluster Cl J0023+0423B at z=0.845. Our 3{sigma} flux limits correspond to an SFR of 0.24h_100_^-2^M_{sun}_/yr, and our minimum reliable H{alpha}+[NII] equivalent width is greater than 10{AA}, demonstrating that near-infrared narrow-band imaging can sample the star-forming galaxy population in distant clusters. Comparison with spectroscopy shows that the number of false detections is low (9%+/-6%) and that our H{alpha} equivalent widths are correlated with spectroscopically determined [O II] equivalent widths. A magnitude-limited spectroscopic survey conducted over the same area missed 70% of the star-forming galaxies and 65% of the integrated star formation. Using Hubble Space Telescope Wide Field Planetary Camera 2 Archive images, we fit Sersic profiles to all galaxies with significant narrow-band equivalent widths and find that equivalent width decreases as the steepness of galaxy profile increases.
- ID:
- ivo://CDS.VizieR/J/MNRAS/431/2
- Title:
- H{alpha} fluxes of Galactic planetary nebulae
- Short Name:
- J/MNRAS/431/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalogue of new integrated H{alpha} fluxes for 1258 Galactic planetary nebulae (PNe), with the majority, totalling 1234, measured from the Southern H{alpha} Sky Survey Atlas (SHASSA) and/or the Virginia Tech Spectral-line Survey (VTSS). Aperture photometry on the continuum-subtracted digital images was performed to extract H{alpha}+[NII] fluxes in the case of SHASSA, and H{alpha} fluxes from VTSS. The [NII] contribution was then deconvolved from the SHASSA flux using spectrophotometric data taken from the literature or derived by us. Comparison with previous work shows that the flux scale presented here has no significant zero-point error. Our catalogue is the largest compilation of homogeneously derived PN fluxes in any waveband yet measured, and will be an important legacy and fresh benchmark for the community. Amongst its many applications, it can be used to determine statistical distances for these PNe, determine new absolute magnitudes for delineating the faint end of the PN luminosity function, provide baseline data for photoionization and hydrodynamical modelling, and allow better estimates of Zanstra temperatures for PN central stars with accurate optical photometry. We also provide total H{alpha} fluxes for another 75 objects which were formerly classified as PNe, as well as independent reddening determinations for ~270 PNe, derived from a comparison of our H{alpha} data with the best literature H{beta} fluxes. In an appendix, we list corrected H{alpha} fluxes for 49 PNe taken from the literature, including 24 PNe not detected on SHASSA or VTSS, re-calibrated to a common zero-point.
- ID:
- ivo://CDS.VizieR/J/ApJ/549/820
- Title:
- H{alpha} flux of ACCG 114 galaxies
- Short Name:
- J/ApJ/549/820
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a wide-field survey for H{alpha}-emitting galaxies in the cluster AC 114 at z=0.32. Spectra centered on H{alpha} at the cluster redshift have been obtained for 586 galaxies to I_tot_~22 out to a radius of ~h_50_^-1^Mpc. At most, only ~10% of these were found to be H{alpha}-emitting cluster members. These objects are predominantly blue and of late-type spiral morphology, consistent with them hosting star formation. However, ~65% of the cluster members classified morphologically as spirals (with HST) have no detectable H{alpha} emission; star formation and morphological evolution in cluster galaxies appear to be largely decoupled. Changes in the H{alpha} detection rate and the strength of H{alpha} emission with environment (as traced by local galaxy density) are found to be weak within the region studied. Star formation within the cluster members is also found to be strongly and uniformly suppressed with the rates inferred from the H{alpha} emission not exceeding 4M_{sun}_/yr, and AC 114's H{alpha} luminosity function being an order of magnitude below that observed for field galaxies at the same redshift. None of the galaxies detected have the high star formation rates associated with "starburst" galaxies; however, this may still be reconcilable with the known (8%+/-3%) fraction of "post-starburst" galaxies within AC 114, given the poorly determined but short lifetimes of starbursts and the possibility that much of the associated star formation is obscured by dust.