J/AJ/150/108 Spectroscopy and HST imaging in ONC (O'Dell+, 2015)
The nature and frequency of outflows from stars in the central Orion Nebula
Cluster.
O'Dell C.R., Ferland G.J., Henney W.J., Peimbert M., Garcia-Diaz MA.T.,
Rubin R.H.
<Astron. J., 150, 108 (2015)>
=2015AJ....150..108O 2015AJ....150..108O (SIMBAD/NED BibCode)
ADC_Keywords: Nebulae ; Clusters, open ; Radial velocities
Keywords: HII regions - ISM: individual: (Orion Nebula,NGC 1976,Orion-South) -
protoplanetary disks
Abstract:
Recent Hubble Space Telescope images have allowed the determination
with unprecedented accuracy of motions and changes of shocks within
the inner Orion Nebula. These originate from collimated outflows from
very young stars, some within the ionized portion of the nebula and
others within the host molecular cloud. We have doubled the number of
Herbig-Haro objects known within the inner Orion Nebula. We find that
the best-known Herbig-Haro shocks originate from relatively few stars,
with the optically visible X-ray source COUP 666 driving many of them.
While some isolated shocks are driven by single collimated outflows,
many groups of shocks are the result of a single stellar source having
jets oriented in multiple directions at similar times. This explains
the feature that shocks aligned in opposite directions in the plane of
the sky are usually blueshifted because the redshifted outflows pass
into the optically thick photon-dominated region behind the nebula.
There are two regions from which optical outflows originate for which
there are no candidate sources in the SIMBAD database.
Description:
We are able to draw on both new and existing observational data for
both imaging and spectroscopy. Since the ionization range of the Orion
Nebula is quite low, we use the high signal-to-noise ratio (S/N) F658N
and F502N images in our analysis
Our new imaging observations were made with Hubble Space Telescope
(HST)'s WFC3 as part of program GO 12543. Observations were made (2012
January 7) with the narrowband emission line filters F487N
(Hβ409s), F502N ([OIII]348s), F656N (Hα349s), F658N
([NII]602s), and F673N ([SII]700s), in addition to observations with
the continuum sampling intermediate-width filter F547M (348s). The
characteristics of these filters and their calibration have been
described by O'Dell et al. (2013AJ....145...92O 2013AJ....145...92O). The images are the
highest angular resolution (0.04''/pixel sampling) optical images of a
portion of the Huygens Region. When used alone, we employed the
original images in combination with one another. When used for
comparison with earlier (undersampled) WFPC2 images (0.0996''/pixel),
we processed them with IRAF task "Gauss" to match their broader image
cores. We have been able to use earlier HST observations made with the
WFPC2 (program GO 5085 (FOV5) on MJD49737; program GO 5469 on
MJD49797; program GO 11038 (FOV1) on MJD54406; program GO 12543 on
MJD55935).
The most useful data set of spectra is the compilation of north-south
orientation long-slit spectra by Garcia-Diaz et al.
(2008RMxAA..44..181G 2008RMxAA..44..181G). In addition to their original observations
(Garcia-Diaz & Henney, 2007AJ....133..952G 2007AJ....133..952G) in low-ionization lines,
they recalibrate the high-ionization spectra of Doi et al. 2004 (cat.
J/AJ/127/3456) and present combined results for emission lines from a
wide variety of ionization states ([OI]630.0nm, [SII]671.6nm+673.1nm,
[NII]658.4nm, [SIII]631.2nm, Hα656.3nm, [OIII]500.7nm)
calibrated to 2km/s accuracy and a resolution of about 10km/s. We will
refer to this as the Spectroscopic Atlas, or simply the Atlas. New
observations were made at the San Pedro Martir Observatory in 2013
February in the [OIII] 500.7nm line in essentially the same manner as
the earlier low-ionization line observations, except that the slit was
oriented east-west. The slit center was at 5:35:15.9. Fifteen spectra
were obtained in steps of 1.4'' starting at 23'' south of
θ1Ori C and proceeding south. Their total exposure time in
each slit of 300 or 600s, depending on the source brightness, with the
2.1m telescope's MEZCAL spectrograph gave higher-S/N images than the
earlier observations made at the Kitt Peak National Observatory with
the 4m telescope's echelle spectrograph by Doi et al. 2004 (cat.
J/AJ/127/3456). The [NII] 658.3nm and [OIII] 500.7nm archived spectra
had an instrumental FWHM intensity of about 10km/s, and the new [OIII]
spectra's FWHM are slightly smaller. The quadratic addition of the
instrumental and thermal FWHM values gives an expected observed FWHM
of 11.5km/s for [NII] and 11.4km/s for [OIII].
The tangential velocities determined from HST images are presented in
Table6. The radial velocities of features not directly associated with
the Main Ionization Front (MIF) are presented in Table7, using data
from the spectroscopic Atlas.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table6.dat 47 177 Tangential velocities
table7.dat 38 195 Radial Velocities outside those of the Main
Ionization Front (MIF)
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/AJ/146/85 : Spectral types of optical stars in ONC (Hillenbrand+, 2013)
J/ApJS/207/10 : HST Treasury Program on the ONC (Robberto+, 2013)
J/ApJS/183/261 : Optical photometry of the ONC (Da Rio+, 2009)
J/ApJ/697/1103 : Kinematics of Orion Nebula Cluster (Tobin+, 2009)
J/ApJ/677/401 : Xray properties of protostars in ONC (Prisinzano+, 2008)
J/AJ/136/2136 : HST/ACS Atlas of Great Orion Nebula proplyds (Ricci+, 2008)
J/AJ/129/1534 : Mid-IR photometry in the Orion Nebula (Robberto+, 2005)
J/AJ/127/3456 : Internal velocities in the Orion Nebula (Doi+, 2004)
J/AJ/125/277 : High proper motions in central Orion nebula (O'Dell+, 2003)
J/AJ/124/445 : Internal velocities in Orion Nebula (Doi+, 2002)
J/ApJ/574/258 : X-ray-emitting young stars in Orion nebula (Feigelson+, 2002)
J/A+A/396/513 : Stellar Rotation in the Orion Nebula Cluster (Herbst+, 2002)
J/A+A/392/239 : IR survey of outflows in Orion A (Stanke+, 2002)
J/ApJ/549/441 : Chandra observations of Orion Trapezium (Schulz+, 2001)
J/ApJ/540/236 : KH photometry of Orion Nebula Cluster (Hillenbrand+, 2000)
J/AJ/117/1375 : Orion Trapezium cluster (Simon+, 1999)
J/AJ/113/1733 : Orion Nebula Cluster population (Hillenbrand 1997)
J/AJ/111/846 : Orion HST survey (O'Dell+ 1996)
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Hour of Right Ascension (J2000) (G1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (G1)
7- 10 F4.1 s RAs Second of Right Ascension (J2000) (G1)
12 A1 --- DE- Sign of the Declination (J2000) (G1)
13- 14 I2 deg DEd Degree of Declination (J2000) (G1)
16- 17 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
19- 20 I2 arcsec DEs Arcsecond of Declination (J2000) (G1)
22- 23 A2 --- --- [LV]
25- 31 A7 --- Name Position designation (G1)
33- 35 I3 deg PA1 [9/349]? Position angle [OIII] (1)
37- 39 I3 km/s Vtan1 [-75/161]? Tangential velocity [OIII] (1)
41- 43 I3 deg PA2 [6/342]? Position angle [NII] (2)
45- 47 I3 km/s Vtan2 [6/159]? Tangential velocity [NII] (2)
--------------------------------------------------------------------------------
Note (1): From the narrowband emission line filter F502N ([OIII]348s).
Note (2): From the narrowband emission line filter F658N ([NII]602s).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 h RAh Hour of Right Ascension (J2000) (G1)
4- 5 I2 min RAm Minute of Right Ascension (J2000) (G1)
7- 10 F4.1 s RAs Second of Right Ascension (J2000) (G1)
12 A1 --- DE- Sign of the Declination (J2000) (G1)
13- 14 I2 deg DEd Degree of Declination (J2000) (G1)
16- 17 I2 arcmin DEm Arcminute of Declination (J2000) (G1)
19- 20 I2 arcsec DEs Arcsecond of Declination (J2000) (G1)
22- 28 A7 --- Name Position designation (G1)
30- 33 I4 km/s HRV1 [-67/151]? Heliocentric radial velocity in
[OIII] 500.7nm (1)
35- 38 I4 km/s HRV2 [-100/25]? Heliocentric radial velocity in
[NII] 658.3nm (1)
--------------------------------------------------------------------------------
Note (1): Subtract -18.1km/s for Local Standard of Rest (LSR).
--------------------------------------------------------------------------------
Note (G1): O'Dell & Wen (1994ApJ...436..194O 1994ApJ...436..194O) introduced a position-based
designation system that has come into common use. It drew on the fact that
most of the objects within the Huygens Region fall near θ1 Ori C
and the designations are simply the abbreviated coordinates. For example,
θ1 Ori C would be designated as 165-323, that is, the R.A. values
were rounded to 0.1s, with 5:35 deleted, and declination values to 1'',
with -5:2 deleted. The positions in Tables 6 and 7 were added at CDS
following the position-based designation system.
History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 01-Feb-2016