J/ApJ/478/603 L1448 & L 1455 new Herbig-Haro flows (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 (SIMBAD/NED BibCode)
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. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 77 24 L1448 HH objects table2 77 11 L1455 HH objects
Byte-by-byte Description of file: table1 table2
Bytes Format Units Label Explanations
1- 6 A6 --- HH HH name 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 10-18W/m2 SHa Hα flux (2) 36- 39 F4.1 10-18W/m2 S[SII] ? [S II] flux (2) 42- 45 I4 arcsec+2 Area Area 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- 77 A20 --- Source Source name
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 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: Prepared via OCR at CDS.
(End) James Marcout, Patricia Bauer [CDS] 03-Oct-1997
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