scholarly journals H2 emission in the low-ionization structures of the planetary nebulae NGC 7009 and NGC 6543

2020 ◽  
Vol 493 (3) ◽  
pp. 3800-3810 ◽  
Author(s):  
Stavros Akras ◽  
Denise R Gonçalves ◽  
Gerardo Ramos-Larios ◽  
Isabel Aleman
Keyword(s):  
Surface Brightness ◽  
Narrow Band ◽  
Planetary Nebulae ◽  
Molecular Gas ◽  
Signal To Noise ◽  
Molecular Emission ◽  
Diagnostic Diagram ◽  
Molecular Excitation ◽  
The Many

ABSTRACT Despite the many studies in the last decades, the low-ionization structures (LISs) of planetary nebulae (PNe) still hold several mysteries. Recent imaging surveys have demonstrated that LISs are composed of molecular gas. Here, we report H2 emission in the LISs of NGC 7009 and NGC 6543 by means of very deep narrow-band H2 images taken with NIRI@Gemini. The surface brightness of the H2 1-0 S(1) line is estimated to be (0.46–2.9)× 10−4 erg s−1 cm−2 sr−1 in NGC 7009 and (0.29–0.48)× 10−4 erg s−1 cm−2 sr−1 in NGC 6543, with signal-to-noise ratios of 10–42 and 3–4, respectively. These findings provide further confirmation of hidden H2 gas in LISs. The emission is discussed in terms of the recent proposed diagnostic diagram R(H2) = H2 1-0 S(1)/H2 2-1 S(1) versus R(Brγ) = H2 1-0 S(1)/Brγ, which was suggested to trace the mechanism responsible for the H2 excitation. Comparing our observations to shock and ultraviolet (UV) molecular excitation models, as well as a number of observations compiled from the literature showed that we cannot conclude for either UV or shocks as the mechanism behind the molecular emission.

scholarly journals HST Observations of Young Planetary Nebulae

2003 ◽  
Vol 209 ◽  
pp. 481-482 ◽  
Author(s):  
Sun Kwok ◽  
Kate Y.L. Su ◽  
Raghvendra Sahai
Keyword(s):  
Surface Brightness ◽  
Narrow Band ◽  
Planetary Nebulae

Seven compact PNe with high radio surface brightness (and therefore presumably young) were observed with the HST WFPC2 under cycle 8 program 8307 (PI: S. Kwok). Observations were made with three narrow-band filters, F656N (Hα), F658N ([NII]) and F502N ([OIII]). The [NII] images of six of the nebulae are shown in Figure 1.

Narrow-band photometry of Wolf-Rayet stars and planetary nebulae

1990 ◽  
Vol 171 (1-2) ◽  
pp. 157-160
Author(s):  
Eugenio E. Mendoza V.
Keyword(s):  
Narrow Band ◽  
Planetary Nebulae

scholarly journals Mainline and water maser observations of OH/IR stars in the Arecibo sky

1997 ◽  
Vol 180 ◽  
pp. 356-356
Author(s):  
B. M. Lewis
Keyword(s):  
Detection Rate ◽  
Planetary Nebulae ◽  
Complete Sample ◽  
Detection Rates ◽  
Ir Stars ◽  
Circumstellar Shells ◽  
Water Masers ◽  
The Many ◽  
Water Maser

A complete sample of color selected IRAS sources with S(25) ≥ 2 Jy in the Arecibo sky and(0° ≤ δ ≤ 37°) was examined previously for 1612 MHz masers. The resulting set of OH/IR stars has now been searched for mainline OH masers at Arecibo (Lewis 1997) and for 22 GHz water masers at Effelsberg (Engels & Lewis 1996). The high overall detection rate of 61.6% for the mainlines and 54.8% for water is partly a result of deployed sensitivity, and partly due to the many blue objects in the sample. But the detectability of both masers improves when S(25)> 20 Jy, as the accompanying tables show. Still the bluest objects exhibit higher (usually ≥80%) detection rates, while there is a clear decrease in detections from redder shells: this decrease begins circa (25–12) μm=–0.55 for mainline masers, and abruptly circa (25–12) μm = −0.35 for water. These trends adhere to the descriptive sequence of the chronological scenario for masers in circumstellar shells, though a few proto planetary nebulae and very red OH/IR stars have water masers and a few mainline masers are detected in shells with (25-12) μm ≥ −0.2.

scholarly journals Possible evolution of the circum-galactic medium around QSOs with QSO age and cosmic time revealed by Ly α haloes

2019 ◽  
Vol 488 (1) ◽  
pp. 120-134 ◽  
Author(s):  
Rieko Momose ◽  
Tomotsugu Goto ◽  
Yousuke Utsumi ◽  
Tetsuya Hashimoto ◽  
Chia-Ying Chiang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Surface Brightness ◽  
Narrow Band ◽  
Cosmic Time ◽  
Black Hole Mass ◽  
Host Galaxies ◽  
Short Term ◽  
Term Evolution ◽  
Similar Growth ◽  
Lower Redshift

ABSTRACT We first present new Subaru narrow-band observations of the Ly α halo around the quasi-stellar object (QSO) CFHQ J232908−030158 at z = 6.42, which appears the most luminous and extended halo at z > 5 (LLy α = 9.8 × 1043 erg s−1 within 37 pkpc diameter). Then, combining these measurements with available data in the literature, we find two different evolutions of QSOs’ Ly α haloes. First is a possible short-term evolution with QSO age seen in four z > 6 QSOs. We find the anticorrelation between the Ly α halo scales with QSOs’ infrared (IR) luminosity, with J2329−0301’s halo being the brightest and largest. It indicates that ionizing photons escape more easily out to circum-galactic regions when host galaxies are less dusty. We also find a positive correlation between IR luminosity and black hole mass (MBH). Given MBH as an indicator of QSO age, we propose a hypothesis that a large Ly α halo mainly exists around QSOs in the young phase of their activity due to a small amount of dust. The second is an evolution with cosmic time seen over z ∼ 2–5. We find the increase of surface brightness towards lower redshift with a similar growth rate to that of dark matter haloes (DHs) that evolve to MDH = 1012–1013 M⊙ at z = 2. The extent of Ly α haloes is also found to increase at a rate scaling with the virial radius of growing DHs, $r_\text{vir} \propto M_\text{DH}^{1/3}(1+z)^{-1}$. These increases are consistent with a scenario that the circum-galactic medium around QSOs evolves in mass and size keeping pace with hosting DHs.

scholarly journals Molecular and ionized gas kinematics in the GC Radio Arc

2016 ◽  
Vol 11 (S322) ◽  
pp. 133-136
Author(s):  
N. Butterfield ◽  
C.C. Lang ◽  
E. A. C. Mills ◽  
D. Ludovici ◽  
J. Ott ◽  
...  
Keyword(s):  
Star Formation ◽  
Molecular Cloud ◽  
Molecular Clouds ◽  
Radio Continuum ◽  
Molecular Gas ◽  
The South ◽  
Ionized Gas ◽  
Molecular Emission ◽  
Gas Kinematics

AbstractWe present NH3 and H64α+H63α VLA observations of the Radio Arc region, including the M0.20 – 0.033 and G0.10 – 0.08 molecular clouds. These observations suggest the two velocity components of M0.20 – 0.033 are physically connected in the south. Additional ATCA observations suggest this connection is due to an expanding shell in the molecular gas, with the centroid located near the Quintuplet cluster. The G0.10 – 0.08 molecular cloud has little radio continuum, strong molecular emission, and abundant CH3OH masers, similar to a nearby molecular cloud with no star formation: M0.25+0.01. These features detected in G0.10 – 0.08 suggest dense molecular gas with no signs of current star formation.

scholarly journals Surveys of Low Surface Brightness Galaxies by 4415 Films

1994 ◽  
Vol 161 ◽  
pp. 541-544
Author(s):  
S. Phillipps ◽  
Q.A. Parker
Keyword(s):  
Surface Brightness ◽  
Signal To Noise ◽  
The Past ◽  
Cluster Area ◽  
Sky Survey ◽  
Low Surface Brightness ◽  
Low Surface Brightness Galaxies

During the past few years there have been a number of surveys for low surface brightness galaxies (LSBGs). Searches using both photographic and CCD data have shown that LSBGs are actually very numerous (Impey, Bothun & Malin 1987; Irwin et al. 1990). However, they are seriously biased against in any random sky survey, and even in a cluster area there are inherent size and signal-to-noise problems. The number of objects we can detect are therefore limited in two ways.

scholarly journals Kinematics of Planetary Nebulae in M51's Tidal Tail

2003 ◽  
Vol 209 ◽  
pp. 633-634
Author(s):  
John J. Feldmeier ◽  
J. Christopher Mihos ◽  
Patrick R. Durrell ◽  
Robin Ciardullo ◽  
George H. Jacoby
Keyword(s):  
Surface Brightness ◽  
Numerical Models ◽  
Planetary Nebulae ◽  
Tidal Tail ◽  
Low Surface Brightness ◽  
Galaxy Interaction ◽  
Self Consistent ◽  
The Galaxy ◽  
Interacting Systems ◽  
Kinematic Properties

The galaxy pair NGC 5194/95 (M51) is one of the closest and best known interacting systems. Despite its notoriety, however, many of its features are not well studied. Extending westward from NGC 5195 is a low surface brightness tidal tail, which can only be seen in deep broadband exposures. Our previous [O III] λ5007 planetary nebulae (PN) survey of M51 recovered this tidal tail, and presented us with a opportunity to study the kinematics of a galaxy interaction in progress. We report the results of a spectroscopy survey of the PN, aimed at determining their kinematic properties. We then use these data to constrain new self-consistent numerical models of the system.

scholarly journals The Relationship Between Gas and Cirrus Dust Filaments at the Edge of the Expanding Shell in Eridanus

1990 ◽  
Vol 139 ◽  
pp. 235-236
Author(s):  
G. L. Verschuur ◽  
F. Verter ◽  
L. J. Rickard ◽  
D. T. Leisawitz
Keyword(s):  
High Resolution ◽  
Surface Brightness ◽  
Neutral Hydrogen ◽  
Scale Structure ◽  
Small Scale ◽  
Molecular Gas ◽  
Small Scale Structure ◽  
Point To Point ◽  
The Relationship ◽  
Co Observations

At the boundary of a large expanding shell in Eridanus around l = 187°, b = −50° the morphology observed in the HI emission is well mimicked by the 100 μm surface brightness but with associated structures offset by as much as 0.°5. A point-to-point comparison between I100μm and NHI in filaments of neutral hydrogen and dust (IR cirrus) produces only a weak dependence. However, when I100μm at a cirrus dust peak is compared with NHI at the associated H i peak, a relationship closer to that reported by other workers is found. Preliminary CO observations have set low limits on the molecular gas in these filaments. Since the H i and dust in our region are associated with a large expanding shell (or superbubble), shocks may be responsible for separation of gas and dust. The existence of small-scale structure in both the HI and IR is noted. We conclude that attempts to correlate HI and IR must invoke high-resolution area surveys.

scholarly journals Opening PANDORA’s box: APEX observations of CO in PNe

2018 ◽  
Vol 618 ◽  
pp. A91 ◽  
Author(s):  
L. Guzman-Ramirez ◽  
A. I. Gómez-Ruíz ◽  
H. M. J. Boffin ◽  
D. Jones ◽  
R. Wesson ◽  
...  
Keyword(s):  
Column Density ◽  
Planetary Nebulae ◽  
Close Binaries ◽  
Physical Parameters ◽  
Molecular Gas ◽  
Intermediate Mass Stars ◽  
Circumstellar Shells ◽  
Large Survey ◽  
Late Stages ◽  
The Universe

Context. Observations of molecular gas have played a key role in developing the current understanding of the late stages of stellar evolution. Aims. The survey Planetary nebulae AND their cO Reservoir with APEX (PANDORA) was designed to study the circumstellar shells of evolved stars with the aim to estimate their physical parameters. Methods. Millimetre carbon monoxide (CO) emission is the most useful probe of the warm molecular component ejected by low- to intermediate-mass stars. CO is the second-most abundant molecule in the Universe, and the millimetre transitions are easily excited, thus making it particularly useful to study the mass, structure, and kinematics of the molecular gas. We present a large survey of the CO (J = 3−2) line using the Atacama Pathfinder EXperiment (APEX) telescope in a sample of 93 proto-planetary nebulae and planetary nebulae. Results. CO (J = 3−2) was detected in 21 of the 93 objects. Only two objects (IRC+10216 and PN M2-9) had previous CO (J = 3−2) detections, therefore we present the first detection of CO (J = 3−2) in the following 19 objects: Frosty Leo, HD 101584, IRAS 19475+3119, PN M1-11, V* V852 Cen, IC 4406, Hen 2-113, Hen 2-133, PN Fg 3, PN Cn 3-1, PN M2-43, PN M1-63, PN M1-65, BD+30 3639, Hen 2-447, Hen 2-459, PN M3-35, NGC 3132, and NGC 6326. Conclusions. CO (J = 3−2) was detected in all 4 observed pPNe (100%), 15 of the 75 PNe (20%), one of the 4 wide binaries (25%), and in 1 of the 10 close binaries (10%). Using the CO (J = 3−2) line, we estimated the column density and mass of each source. The H2 column density ranges from 1.7 × 1018 to 4.2 × 1021 cm−2 and the molecular mass ranges from 2.7 × 10−4 to 1.7 × 10−1 M⊙.

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