Searcharxiv⌕ Search

arXiv subjects

L. Olguín

Publications and source records attributed to L. Olguín.

16 recordsLinked to original sources
arXiv2025

Confirmation and characterization of Galactic planetary nebulae: insights from a spectroscopic study

We present a spectroscopic investigation of 25 objects previously reported as possible Planetary Nebulae (PNe) in recent catalogs to obtain their physical properties and to establish their true nature. We found 11 objects showing intense emission lines, 11 where it was not possible to measure $\mathrm{Hβ}$, and three where no lines are present. We have used diagnostic diagrams to confirm the true PN nature for eight objects. We obtained elemental abundances for three objects whose values are in agreement with the PNe mean values for our Galaxy. Four objects show [N II] $λ$6583 more intense than $\mathrm{Hα}$, and for two of them, this can be explained by the presence of shocks in the gas. Finally, we report angular sizes based on $\mathrm{Hα}$ and [O III] $λ$5007 emission.

astro-ph.SR↗
arXiv2024

Morphokinematical study of the planetary nebula Me2-1: Unveiling its point-symmetric and unusual physical structure

(Abridged) We present narrow-band images in several emission lines, and high- and intermediate-resolution long-slit spectra of Me2-1 to investigate its morphology and 3D structure, its physical parameters and chemical abundances. We identified in Me2-1: an elliptical ring; two elongated, curved structures (caps) that contain three pairs of bright point-symmetric (PS) knots; a shell interior of the ring; and a faint halo or attached shell. The caps are observed in all images, the PS knots only in the low-excitation emission line ones. These structures are also identified in the high-resolution long-slit spectra. The 3D reconstruction shows that Me2-1 consists of a ring seen almost pole-on, and a virtually spherical shell, to which the caps and PS knots are attached. Caps and PS knots most probably trace the sites where high-velocity collimated bipolar outflows, ejected along a wobbling axis, collide with the spherical shell, are slowed down, and remain attached to it. Although the main excitation mechanism in Me2-1 is found to be photoionization, a contribution of shocks in the PS knots is suggested by their emission line ratios. The combination of collimated outflows and a ring with a spherical shell is unusual among planetary nebulae. We speculate that two planets, each with less than one Jupiter mass, could be involved in the formation of Me2-1 if both enter a common envelope evolution during the asymptotic giant branch phase of the progenitor. One planet is tidally disrupted, forming an accretion disk around the central star, from which collimated bipolar outflows are ejected; the other planet survives, causing wobbling of the accretion disk. The derived physical parameters and chemical abundances are similar to those obtained in previous analyses, with the abundances also pointing to a low-mass progenitor of Me2-1.

astro-ph.GA↗
arXiv2023

The origin of the planetary nebula M 1-16. A morphokinematic and chemical analysis

We investigated the origin of the Planetary Nebula (PN) M 1-16 using narrow-band optical imaging, and high- and low-resolution optical spectra to perform a detailed morpho-kinematic and chemical studies. M 1-16 is revealed to be a multipolar PN that predominantly emits in [O III] in the inner part of the nebula and [N II] in the lobes. A novel spectral unsharp masking technique was applied to the position-velocity (PV) maps to reveal a set of multiple structures at the centre of M 1-16 spanning radial velocities from $-$40km$\,$s$^{-1}$ to 20km$\,$s$^{-1}$, with respect to the systemic velocity. The morpho-kinematic model indicates that the deprojected velocity of the lobe outflows are $\geq$100km$\,$s$^{-1}$, and particularly the larger lobes and knots have a deprojected velocity of $\simeq$350km$\,$s$^{-1}$; the inner ellipsoidal component has a deprojected velocity of $\simeq$29km$\,$s$^{-1}$. A kinematical age of $\sim$8700yr has been obtained from the model assuming a homologous velocity expansion law and a distance of 6.2$\pm$1.9kpc. The chemical analysis indicates that M 1-16 is a Type I PN with a central star of PN (CSPN) mass in the range of $\simeq$0.618-0.713M$_\odot$ and an initial mass for the progenitor star between 2.0 and 3.0M$_\odot$ (depending on metallicity). An $T_\mathrm{eff}\simeq$140$\,$000K and log$(L/L_{\odot})$=2.3 was estimated using the 3MdB photoionisation models to reproduce the ionisation stage of the PN. All of these results have led us to suggest that M 1-16 is an evolved PN, contrary to the scenario of proto-PN suggested in previous studies. We propose that the mechanism responsible for the morphology of M 1-16 is related to the binary (or multiple star) evolution scenario.

astro-ph.SR↗
arXiv2021

The reactivation of water maser emission in the planetary nebula IRAS 18061--2505 through a born-again episode

Water maser emitting planetary nebulae (H$_2$O-PNe) are believed to be among the youngest PNe. We present new optical narrow- and broad-band images, intermediate- and high-resolution long-slit spectra, and archival optical images of the H$_2$O-PN IRAS 18061--2505. It appears a pinched-waist bipolar PN consisting of knotty lobes with some point-symmetric regions, a bow-shock near the tip of each lobe, and a very compact inner nebula where five components are identified in the spectra by their kinematic and emission properties. The water masers most probably reside in an oxygen-rich ring tracing the equatorial region of the bipolar lobes. These two structures probably result from common envelope evolution plus several bipolar and non-bipolar collimated outflows that have distorted the lobes. The bow-shocks could be related to a previous phase to that of common envelope. The inner nebula may be attributed to a late or very late thermal pulse that occurred before 1951.6 when it was not detectable in the POSSI-Blue image. Chemical abundances and other properties favour a 3--4 M$_{\odot}$ progenitor, although if the common envelope phase accelerated the evolution of the central star, masses <1.5 M$_{\odot}$ cannot be discarded. The age of the bipolar lobes is incompatible with the existence of water masers in IRAS 18061--2505, which may have been lately reactivated through shocks in the oxygen-rich ring, that are generated by the thermal pulse, implying that this PN is not extremely young. We discuss H$_2$O-PNe and possibly related objects in the light of our results for IRAS 18061--2505.

astro-ph.GA↗
arXiv2019

From outburst to quiescence: spectroscopic evolution of V1838 Aql imbedded in a bow-shock nebula

We analyse new optical spectroscopic, direct-image and X-ray observations of the recently discovered a high proper motion cataclysmic variable V1838 Aql. The data were obtained during its 2013 superoutburst and its subsequent quiescent state. An extended emission around the source was observed up to 30 days after the peak of the superoutburst, interpreted it as a bow--shock formed by a quasi-continuous outflow from the source in quiescence. The head of the bow--shock is coincident with the high--proper motion vector of the source ($v_{\perp}=123\pm5$ km s$^{-1}$) at a distance of $d=202\pm7$ pc. The object was detected as a weak X-ray source ($0.015\pm0.002$ counts s$^{-1}$) in the plateau of the superoutburst, and its flux lowered by two times in quiescence (0.007$\pm$0.002 counts s$^{-1}$). Spectroscopic observations in quiescence we confirmed the orbital period value $P_{\rm{orb}}=0.0545\pm 0.0026$ days, consistent with early-superhump estimates, and the following orbital parameters: $γ= -21\pm3$ km s$^{-1}$ and $K_1 = 53\pm3$ km s$^{-1}$. The white dwarf is revealed as the system approaches quiescence, which enables us to infer the effective temperature of the primary $T_{eff}=11,600\pm400$K. The donor temperature is estimated $\lesssim 2200$K and suggestive of a system approaching the period minimum. Doppler maps in quiescence show the presence of the hot spot in HeI line at the expected accretion disc-stream shock position and an unusual structure of the accretion disc in H$α$.

astro-ph.SR↗
arXiv2018

The interaction of the halo around the butterfly planetary nebula NGC650-1 with the interstellar medium

With its bright and wide equatorial waist seen almost edge-on (the butterfly body) and the faint and broad bipolar extensions (the butterfly wings), NGC650-1 is the archetypical example of bipolar planetary nebula (PN) with butterfly morphology. We present here deep high-resolution broad- and narrow-band optical images that expose the rich and intricate fine structure of this bipolar PN, with small-scale bubble-like features and collimated outflows. A SHAPE spatio-kinematical model indicates that NGC650-1 has a broad central torus with an inclination angle of 75 degrees with respect to the line of sight, whereas that of the bipolar lobes, which are clearly seen in the position-velocity maps, is 85 degrees. Large field of view deep images show, for first time, an arc-like diffuse envelope in low- and high-excitation emission lines located up to 180 arcsec towards the East-Southeast of the central star, well outside the main nebula. This morphological component is confirmed by Spitzer MIPS and WISE infrared imaging, as well as by long-slit low- and high-dispersion optical spectroscopic observations. HST images of NGC650-1 obtained at two different epochs (14 yrs apart), reveal the proper motion of the central star along this direction. We propose that this motion of the star through the interstellar medium compresses the remnant material of a slow Asymptotic Giant Branch wind, producing this bow-shock-like feature.

astro-ph.SR↗
arXiv2017

Catching a Grown-Up Starfish Planetary Nebula: I. Morpho-Kinematical study of PC 22

We present the first part of an investigation on the planetary nebula (PN) PC 22 which focuses on the use of deep imaging and high resolution echelle spectroscopy to perform a detailed morpho-kinematical analysis. PC 22 is revealed to be a multipolar PN emitting predominantly in [O III] and displaying multiple non-symmetric outflows. Its central region is found to be also particularly inhomogeneous with a series of low ionization structures (knots) located on the path of the outflows. The morpho-kinematical model obtained with SHAPE indicates that i) the de-projected velocities of the outflows are rather large, > 100 km/s, while the central region has expansion velocities in the range ~25 to ~45 km/s following the "Wilson effect", ii) the majority of the measured structures share similar inclination, ~100 degrees, i.e. they are coplanar, and iii) all outflows and lobes are coeval (within the uncertainties). All these results make us to suggest that PC 22 is an evolved starfish PN. We propose that the mechanism responsible for the morphology of PC 22 consists of a wind-shell interaction, where the fast post-AGB wind flows through a filamentary AGB shell with some large voids.

astro-ph.SR↗
arXiv2016

History of the mass ejection in K 4-37: from the AGB to the evolved planetary nebula phase

We present narrow-, broad-band, and WISE archive images, and high- and intermediate-resolution long-slit spectra of K 4-37, a planetary nebula that has never been analyzed in detail. Although K 4-37 appears bipolar, the morphokinematical analysis discloses the existence of three distinct axes and additional particular directions in the object, indicating that K 4-37 is a multi-axis planetary nebula that has probably been shaped by several bipolar outflows at different directions. A 4-6 M$_{\odot}$ main-sequence progenitor is estimated from the derived high nebular He and N abundances, and very high N/O abundance ratio ($\sim$2.32). The general properties are compatible with K 4-37 being a highly evolved planetary nebula located at $\sim$14 kpc. The WISE image at 22 $μ$m reveals K 4-37 to be surrounded by a large ($\sim$13$\times$8 pc$^2$) elliptical detached shell probably related to material ejected from the AGB progenitor. The observed elliptical morphology suggests deformation of an originally spherical AGB shell by the ISM magnetic field or by the influence of a companion. We compare K 4-37 and NGC 6309 and found remarkable similarities in their physical structure but noticeably different chemical abundances that indicate very different progenitor mass. This strongly suggests that, irrespective of the initial mass, their (presumably binary) central stars have shared a very similar mass ejection history.

astro-ph.SR↗
arXiv2016

Observations of the planetary nebula RWT 152 with OSIRIS/GTC

RWT 152 is one of the few known planetary nebulae with an sdO central star. We present subarcsecond red tunable filter Halpha imaging and intermediate-resolution, long-slit spectroscopy of RWT 152 obtained with OSIRIS/GTC with the goal of analyzing its properties. The Halpha image reveals a bipolar nebula with a bright equatorial region and multiple bubbles in the main lobes. A faint circular halo surrounds the main nebula. The nebular spectra reveal a very low-excitation nebula with weak emission lines from H^+, He^+, and double-ionized metals, and absence of emission lines from neutral and single-ionized metals, except for an extremely faint [NII]6584 emission line. These spectra may be explained if RWT 152 is a density-bounded planetary nebula. Low nebular chemical abundances of S, O, Ar, N, and Ne are obtained in RWT 152, which, together with the derived high peculiar velocity ($\sim$ 92-131 km s$^{-1}$), indicate that this object is a halo planetary nebula. The available data are consistent with RWT 152 evolving from a low-mass progenitor ($\sim$ 1 M$_{\odot}$) formed in a metal-poor environment.

astro-ph.SR↗
arXiv2014

The physical structure of planetary nebulae around sdO stars: Abell36, DeHt2, and RWT152

We present narrow-band Halpha and [OIII] images, and high-resolution, long-slit spectra of the planetary nebulae (PNe) Abell36, DeHt2, and RWT152 aimed at studying their morphology and internal kinematics. These data are complemented with intermediate-resolution, long-slit spectra to describe the spectral properties of the central stars and nebulae. The morphokinematical analysis shows that Abell36 consists of an inner spheroid and two bright point-symmetric arcs; DeHt2 is elliptical with protruding polar regions and a bright non-equatorial ring; and RWT152 is bipolar. The formation of Abell36 and DeHt2 requires several ejection events including collimated bipolar outflows that probably are younger than and have disrupted the main shell. The nebular spectra of the three PNe show a high excitation and also suggest a possible deficiency in heavy elements in DeHt2 and RWT152. The spectra of the central stars strongly suggest an sdO nature and their association with PNe points out that they have most probably evolved through the asymptotic giant branch. We analyze general properties of the few known sdOs associated to PNe and find that most of them are relatively or very evolved PNe, show complex morphologies, host binary central stars, and are located at relatively high Galactic latitudes.

astro-ph.SR↗
arXiv2014

First release of the IPHAS Catalogue of New Extended Planetary Nebulae

We present the first results of our search for new, extended Planetary Nebulae (PNe) based on careful, systematic, visual scrutiny of the imaging data from the INT Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS). The newly uncovered PNe will help to improve the census of this important population of Galactic objects that serve as key windows into the late stage evolution of low to intermediate mass stars. They will also facilitate study of the faint end of the ensemble Galactic PN luminosity function. The sensitivity and coverage of IPHAS allows PNe to be found in regions of greater extinction in the Galactic Plane and/or those PNe in a more advanced evolutionary state and at larger distances compared to the general Galactic PN population. Using a set of newly revised optical diagnostic diagrams in combination with access to a powerful, new, multi-wavelength imaging database, we have identified 159 true, likely and possible PNe for this first catalogue release. The ability of IPHAS to unveil PNe at low Galactic latitudes and towards the Galactic Anticenter, compared to previous surveys, makes this survey an ideal tool to contribute to the improvement of our knowledge of the whole Galactic PN population

astro-ph.SR↗
arXiv2013

Detection of a multi-shell planetary nebula around the hot subdwarf O-type star 2MASS J19310888+4324577

(Abridged) The origin of hot subdwarf O-type stars (sdOs) remains unclear since their discovery in 1947. Among others, a post-Asymptotic Giant Branch (post-AGB) origin is possible for a fraction of sdOs. We are involved in a comprehensive ongoing study to search for and to analyze planetary nebulae (PNe) around sdOs with the aim of establishing the fraction and properties of sdOs with a post-AGB origin. We use deep Halpha and [OIII] images of sdOs to detect nebular emission and intermediate resolution, long-slit optical spectroscopy of the detected nebulae and their sdO central stars. These data are complemented with other observations for further analysis of the detected nebulae. We report the detection of an extremely faint, complex PN around 2MASS J19310888+4324577 (2M1931+4324), a star classified as sdO in a binary system. The PN shows a bipolar and an elliptical shell, whose major axes are oriented perpendicular to each other, and high-excitation structures outside the two shells. WISE archive images show faint, extended emission at 12 and 22 microns in the inner nebular regions. The internal nebular kinematics is consistent with a bipolar and a cylindrical/ellipsoidal shell, in both cases with the main axis mainly perpendicular to the line of sight. The nebular spectrum only exhibits Halpha, Hbeta and [OIII]4959,5007 emission lines, but suggests a very low-excitation ([OIII]/Hbeta = 1.5), in strong contrast with the absence of low-excitation emission lines. The spectrum of 2M1931+4324 presents narrow, ionized helium absorptions that confirm the previous sdO classification and suggest an effective temperature >= 60000 K. The binary nature of 2M1931+4324, its association with a complex PN, and several properties of the system provide strong support for the idea that binary central stars are a crucial ingredient in the formation of complex PNe.

astro-ph.SR↗
arXiv2013

New Galactic supernova remnants discovered with IPHAS

As part of a systematic search programme of a 10-degree wide strip of the Northern Galactic plane we present preliminary evidence for the discovery of four (and possibly five) new supernova remnants (SNRs). The pilot search area covered the 19-20 hour right ascension zone sampling from +20 to +55 degrees in declination using binned mosaic images from the INT Photometric H-alpha Survey (IPHAS). The optical identification of the candidate SNRs was based mainly on their filamentary and arc-like emission morphologies, their apparently coherent, even if fractured structure and clear disconnection from any diffuse neighbouring HII region type nebulosity. Follow-up optical spectroscopy was undertaken, sampling carefully across prominent features of these faint sources. The resulting spectra revealed typical emission line ratios for shock excited nebulae which are characteristic of SNRs, which, along with the latest diagnostic diagrams, strongly support the likely SNR nature of these sources: G038.7-1.3 (IPHASX J190640.5+042819); G067.6+0.9 (IPHASX J195744.9+305306); G066.0-0.0 (IPHASX J195749.2+290259) and G065.8-0.5 (IPHASX J195920.4+283740). A fifth possible younger, higher density nebula SNR candidate, G067.8+0.5 (IPHASX J200002.4+305035) was discovered about 5 arcmins to the west of IPHASX J195744.9+305306, and warrants further study. A multi-wavelength cross-check from available archived data in the regions of these candidates was also performed with a focus on possible radio counterparts.

astro-ph.SR↗
arXiv2010

Observational Study of the Multistructured Planetary Nebula NGC 7354

We present an observational study of the planetary nebula (PN) NGC 7354 consisting of narrowband Halpha and [NII]6584 imaging as well as low- and high-dispersion long-slit spectroscopy and VLA-D radio continuum. According to our imaging and spectroscopic data, NGC 7354 has four main structures: a quite round outer shell and an elliptical inner shell, a collection of low-excitation bright knots roughly concentrated on the equatorial region of the nebula, and two symmetrical jet-like features, not aligned either with the shells' axes, or with each other. We have obtained physical parameters like electron temperature and electron density as well as ionic and elemental abundances for these different structures. Electron temperature and electron density slightly vary throughout the nebula. The local extinction coefficient c_Hbeta shows an increasing gradient from south to north and a decreasing gradient from east to west consistent with the number of equatorial bright knots present in each direction. Abundance values show slight internal variations but most of them are within the estimated uncertainties. In general, abundance values are in good agreement with the ones expected for PNe. Radio continuum data are consistent with optically thin thermal emission. We have used the interactive three-dimensional modeling tool SHAPE to reproduce the observed morphokinematic structures in NGC 7354 with different geometrical components. Our SHAPE model is in very good agreement with our imaging and spectroscopic observations. Finally, after modeling NGC 7354 with SHAPE, we suggest a possible scenario for the formation of the nebula.

astro-ph.SR↗
arXiv2008

The physical structure of the point-symmetric and quadrupolar planetary nebula NGC 6309

We analyse the point-symmetric planetary nebula NGC 6309 in terms of its three-dimensional structure and of internal variations of the physical conditions to deduce the physical processes involved in its formation. We used VLA-D 3.6-cm continuum, ground-based, and HST-archive imaging as well as long slit high- and low-dispersion spectroscopy. The low-dispersion spectra indicate a high excitation nebula, with low to medium variations of its internal physical conditions. In the optical images, the point-symmetric knots show a lack of [NII] emission as compared with similar features previously known in other PNe. A rich internal structure of the central region is seen in the HST images, resembling a deformed torus. Long slit high-dispersion spectra reveal a complex kinematics in the central region. The spectral line profiles from the external regions of NGC 6309 indicate expanding lobes (~40 km/s) as those generally found in bipolar nebulae. Finally, we have found evidence for the presence of a faint halo, possibly related to the envelope of the AGB-star progenitor. Our data indicate that NGC 6309 is a quadrupolar nebula with two pairs of bipolar lobes whose axes are oriented PA=40 and PA=76. Equatorial and polar velocities for these two pairs of lobes are 29 and 86 km/s for the bipolar system at PA=40 and 25 and 75 km/s for the bipolar system at PA=76. There is also a central torus that is expanding at 25 km/s. Kinematical age for all these structures is around 3700 to 4000 yr. We conclude that NGC 6309 was formed by a set of well-collimated bipolar outflows (jets), which were ejected in the initial stages of its formation as a planetary nebula. These jets carved the bipolar lobes in the previous AGB wind and their remnants are now observed as the point-symmetric knots tracing the edges of the lobes.

astro-ph↗