J/MNRAS/480/1563 Properties of UWISH2 PNe candidates (Jones+, 2018)
The excitation mechanisms and evolutionary stages of UWISH2 planetary nebula
candidates.
Jones A.M., Gledhill T.M., Froebrich D., Smith M.D.
<Mon. Not. R. Astron. Soc., 480, 1563-1579 (2018)>
=2018MNRAS.480.1563J 2018MNRAS.480.1563J (SIMBAD/NED BibCode)
ADC_Keywords: Planetary nebulae ; Interstellar medium ; Infrared ;
Line Profiles
Keywords: ISM: lines and bands - planetary nebulae: general - infrared: ISM
Abstract:
We present medium-resolution K-band long-slit spectroscopy of 29 true,
likely, possible, and candidate Galactic Plane planetary nebulae (PNe)
from the UWISH2 survey, many of which have only been recently
discovered. These objects are bright in molecular hydrogen (H2)
emission, and many have bipolar morphologies. Through the detection of
the Brγ emission line, which traces ionized hydrogen, we find
that the majority of the candidate PNe are indeed likely to be PNe,
while 2 of the targets are more likely young stellar objects (YSOs) or
pre-planetary nebulae (pPNe). We detect Brγ in 13 objects which
have no detection in IPHAS or SHS Hα surveys. This implies that
they are potential members of the little-known optically obscured PN
population, hidden from wide-field optical surveys. We use the spatial
extent of the H2 1-0S(1) and Brγ lines to estimate the
evolutionary stage of our targets, and find that W-BPNe (bipolar PNe
with pinched waist morphologies) are likely to be younger objects,
while R-BPNe (bipolar PNe with large ring structures) are more
evolved. We use line ratios to trace the excitation mechanism of the
H2, and find the 1-0S(1)/2-1S(1) and 1-0S(1)/Brγ ratios are
higher for R-BPNe, implying the H2 is thermally excited. However, in
W-BPNe, these ratios are lower, and so UV-fluorescence may be
contributing to the excitation of H2.
Description:
In this work, we present K-band long-slit spectra of a sample of PNe
and candidate PNe taken from the recent UWISH2 imaging survey (UKIRT
Widefield Infrared Survey for H2) (Froebrich et al.
2011MNRAS.413..480F 2011MNRAS.413..480F). We focus on the mechanisms governing the
excitation of H2, and how these relate to the evolutionary stages and
morphologies of the targets. Along with spectra, we make use of
near-IR H2 and optical Hα imaging, and mid-IR colours where
available. UWISH2 was an unbiased Galactic Plane survey, focused on
the H2 1-0S(1) line at 2.1218µm. Our sample for spectroscopic
follow-up consisted of 29 targets, selected mainly due to their bright
H2 fluxes.
Observations were obtained on 2016 July 22-24, using the Long-slit
Intermediate Resolution Infrared Spectrograph (LIRIS; Acosta Pulido et
al. 2003; Manchado et al. 2003) on the William Herschel Telescope,
located at the Observatorio del Roque de los Muchachos on La Palma,
Canary Islands. LIRIS uses a 1024x1024 HAWAII detector, with a pixel
scale of 0.25 arcsec pixel-1, yielding a field of view of
4.27arcminx4.27arcmin.
Table 1 gives observational details for each target, table 2 contains
the key line flux ratios and table C1 lists all detected emission line
fluxes for each PNe candidate.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 96 29 Observation log and additional information for
the 29 targets
table2.dat 61 49 Key line flux ratios and errors, uncorrected
for extinction
tablec1.dat 126 49 Continuum-subtracted line fluxes and errors for
K-band emission lines
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Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Planetary nebula name (PN GLLL.l+BB.b)
16- 40 A25 --- OtherName Other name associated to the source
42- 50 F9.5 deg RAdeg Right ascension (J2000)
52- 60 F9.5 deg DEdeg Declination (J2000)
62- 65 I4 s Int Integration time
67- 70 F4.2 --- Airmass Airmass
72- 75 A4 --- H2morph Morphology in H2 (1)
77- 83 A7 --- H2size Size in H2 (1)
85- 87 A3 --- Hamorph Morphology in Hα (1)
89- 94 A6 --- Hasize Size in Hα (1)
96 A1 --- PNstatus Planetary nebula status (2)
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Note (1): Morphologies and sizes in H2 and Hα are taken from table A1 of
Gledhill et al. (2018MNRAS.479.3759G 2018MNRAS.479.3759G). Where no Hα morphology
is given, the object is not detected in Hα emission.
Morphologies make use of the 'ERBIAS' classification system
(Parker et al. 2006MNRAS.373...79P 2006MNRAS.373...79P), and sizes are the major and
minor axis dimensions in arcsec.
Note (2): PN status comes from the HASH PN database (Parker, Bojicic & Frew
2016JPhCS.728c2008P 2016JPhCS.728c2008P).
Status as follows:
T = true PNe
L = likely to be PNe
P = possible PNe
C = candidate PNe
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Planetary nebula name (PN GLLL.l+BB.b)
16- 25 A10 --- Region Region of the source
27- 30 F4.1 --- nu1/nu2 ? Ratio of the 1-0S(1) (2.1218µm) and the
2-1S(1) (2.2477µm) H2 lines
32- 34 F3.1 --- e_nu1/nu2 ? Error on nu1/nu2
36- 37 I2 --- nu1/nu3 ?=- Ratio of the 1-0S(1) and the 3-2S(3)
(2.2014µm) H2 lines
39- 40 I2 --- e_nu1/nu3 ?=- Error on nu1/nu3
42- 46 F5.2 --- nu1/Brg ? Ratio of the 1-0S(1) and the Brγ
(2.1661µm) lines
48- 51 F4.2 --- e_nu1/Brg ? Error on nu1/Brg
53- 56 F4.2 --- HeI/Brg ? Ratio of the HeI (2.0587µm) and the
Brγ line
58- 61 F4.2 --- e_HeI/Brg ? Error on HeI/Brg
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Byte-by-byte Description of file: tablec1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 14 A14 --- Name Planetary nebula name (PN GLLL.l+BB.b)
16- 25 A10 --- Region Region of the object
27- 32 F6.1 10-19W/m2 HeI1 ? Continuum-substracted HeI (2.0587µm)
line flux
34- 37 F4.1 10-19W/m2 e_HeI1 ? Error on HeI1
39- 42 F4.1 10-19W/m2 2-1S(3) ? Continuum-substracted 2-1S(3)
(2.0735µm) line flux
44- 47 F4.1 10-19W/m2 e_2-1S(3) ? Error on 2-1S(3) flux
49- 53 F5.1 10-19W/m2 HeI2 ? Continuum-substracted HeI (2.1127µm)
line flux
55- 58 F4.1 10-19W/m2 e_HeI2 ? Error on HeI2
60- 62 I3 10-19W/m2 1-0S(1) Continuum-substracted 1-0S(1)
(2.1218µm) line flux
64- 65 I2 10-19W/m2 e_1-0S(1) Error on 1-0S(1) flux
67- 68 I2 10-19W/m2 2-1S(2) ?=- Continuum-substracted 2-1S(2)
(2.1542µm) line flux
70- 71 I2 10-19W/m2 e_2-1S(2) ?=- Error on 2-1S(2) flux
73- 78 F6.1 10-19W/m2 Brg ? Continuum-substracted Brγ
(2.1661µm) line flux
80- 83 F4.1 10-19W/m2 e_Brg ? Error on Brg
85- 86 I2 10-19W/m2 HeII ?=- Continuum-substracted HeII
(2.1891µm) line flux
88 I1 10-19W/m2 e_HeII ?=- Error on HeII
90- 93 F4.1 10-19W/m2 3-2S(3) ? Continuum-substracted 3-2S(3)
(2.2014µm) line flux
95- 97 F3.1 10-19W/m2 e_3-2S(3) ? Error on 3-2S(3) flux
99-101 I3 10-19W/m2 1-0S(0) Continuum-substracted 1-0S(0)
(2.2233µm) line flux
103-104 I2 10-19W/m2 e_1-0S(0) Error on 1-0S(0) flux
106-109 F4.1 10-19W/m2 2-1S(1) ? Continuum-substracted 2-1S(1)
(2.2477µm) line flux
111-113 F3.1 10-19W/m2 e_2-1S(1) ? Error on 2-1S(1) flux
115-117 I3 10-19W/m2 3-2S(2) ?=- Continuum-substracted 3-2S(2)
(2.2870µm) line flux
119 I1 10-19W/m2 e_3-2S(2) ?=- Error on 3-2S(2) flux
121-123 I3 10-19W/m2 1-0Q(1) Continuum-substracted 1-0Q(1)
(2.4066µm) line flux
125-126 I2 10-19W/m2 e_1-0Q(1) Error on 1-0Q(1) flux
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 17-May-2022