J/ApJ/478/603 New Herbig-Haro flows in L1448 and L1455 (Bally+ 1997)
New Herbig-Haro flows in L1448 and L1455
Bally J., Devine D., Alten V., Sutherland R.S.
<Astrophys. J. 478, 603 (1997)>
=1997ApJ...478..603B 1997ApJ...478..603B
ADC_Keywords: Stars, pre-main sequence ; Radial velocities
Keywords: ISM: individual (L1448) - ISM: jets and outflows -
stars: pre-main-sequence
Abstract:
We present a deep narrowband Hα and [S II] optical survey of a
roughly 1deg2 region containing L1448 and L1455 in the southwestern
region of the Perseus molecular cloud. We report the detection of 13
new groups of Herbig-Haro (HH) objects in this region. The L1448 core
contains eight groups of Herbig-Haro objects (HH 193, HH 194, HH 195,
HH 196, HH 197, HH 267, HH 268, and HH 277). Many of the new HH
objects near L1448 have orientations similar to the L1448C molecular
jet and L1448 IRS3 outflow. All four known infrared sources in L1448
power Herbig-Haro objects. L1448 IRS 1 is the likely source of HH 194,
HH 195E, and possibly HH 268. L1448 IRS 2 drives HH 195, and L1448 IRS
3 may power HH 196 and possibly HH 193. HH 267 and HH 277 lie close to
the axes of the IRS 2 and IRS 3 flows and may also be powered by one
of these sources. Finally, the class 0 source L1448C powers HH 197.
The L1455 core contains five new groups of HH objects (HH 278, HH 279,
HH 280, HH 317, and HH 318). L1455 IRS 1 and L1455 IRS 2 are likely to
power HH objects, but a unique association between each IRAS source
and a specific HH object is difficult to make. Both clouds contain
some HH objects whose driving sources cannot be conclusively
identified. Most of the new HH objects are located near the cloud
edges while some are in the interclump medium (ICM) more than 1pc from
the nearest cloud core or known young stellar object. These
observations provide further evidence that HH flows can extend far
beyond the cloud cores containing their sources, and in some cases
extend over greater distances than associated high-velocity
millimeter-wavelength CO emission. Herbig-Haro objects associated with
the terminal working surfaces of outflows located in the ICM can be
used to probe the nature of the interclump gas in molecular clouds.
The large number of HH objects found in relatively inactive star
forming regions such as L1448 and L1455 indicates that shock heating
and acceleration by protostellar outflows plays an important role in
determining the ionization state and energetics of the ICM that
surrounds low-mass star forming regions.
Description:
Images covering the region to the northwest of L1448 were obtained on
1993-11-01 with the 0.9m f/7.5 Cassegrain telescope Kitt Peak National
Observatory (KPNO) with a Tektronix 2048x2048 pixel CCD (T2KA) which
has a pixel scale of 0.68arcsec/pix and a total field of view of about
23arcmin. Observations in Hα used a narrowband filter centered
at 656.2nm (3nm wide) and 674.5nm (8.3nm wide) for 671.6 and 673.1nm
[SII] lines.
The fields between L1448 and L1455 were observed wth the 1m reflector
at the Mount Laguna observatory operated by San Diego State University
on 1994-11-16, with a Loral 2048x2048 pixel CCD, and interference
filters of width 7nm centered at 673nm ([SII]), 656.3nm Hα), and
665nm (continuum); the field of view is 13arcmin.
Images covering roughly 1sq.deg ontaining L1448 and L1455 were
obtained with the 0.6m Burrell Schmidt camera at KPNO on 1996-12-16,
with a SITE 2048x2048 pixel CCD (2arcsec/pix) and interefernce filters
centered on the Hα and [SII] lines with width=8nm.
High-resolution spectra (R∼6000) were obtained with the 4m Mayall
reflector at KPNO on 1994-11-12/14 and 1996-01-11 using both a 2x5''
slit and a multiaperture slitlet mask on the spectrograph, which gave
a scale of 0.54Å/pix (24km/s resolution).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 76 24 L1448 HH objects
table2.dat 74 11 L1455 HH objects
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [HH]
4- 6 I3 --- HH HH identification number
7 A1 --- m_HH [ABCDE] Multiplicity index on HH
9 I1 h RAh Right ascension (1950)
11- 12 I2 min RAm Right ascension (1950)
14- 17 F4.1 s RAs Right ascension (1950) (1)
20- 21 I2 deg DEd Declination (1950)
23- 24 I2 arcmin DEm Declination (1950)
26- 27 I2 arcsec DEs Declination (1950) (1)
30- 33 F4.1 aW/m2 Ha Hα flux (2)
36- 39 F4.1 aW/m2 [SII] ? [SII] flux (671.6+673.1nm) (2)
42- 45 I4 arcsec+2 Area Area of the source
48- 50 I3 km/s RV ? Radial velocity of the HH object
53- 55 I3 km/s DV ? Line width of the HH object
58- 76 A19 --- Notes Remarks about the source
--------------------------------------------------------------------------------
Note (1): Coordinates are accurate to within a few arcseconds.
Note (2): Line fluxes are in units of 10-15ergs/cm2/s and were
calibrated by observations of the standard star Feige 34. Fluxes were
determined by integrating the emission (summing the counts in each
pixel) over the apparent extent of the HH object, then subtracting the
background integrated over a nearby region of the same size that was
free from HH emission.
--------------------------------------------------------------------------------
History:
* 03-Oct-1997: Prepared via OCR at CDS.
* 03-Jul-2014: Standardized at CDS
(End) James Marcout, Patricia Bauer [CDS] 03-Oct-1997