| NEWS: | New MHOs have recently been added to Puppis (Varricatt 2012), Cassiopeia (Wolf-Chase et al. 2012), Aquila and Serpens (Ioannidis & Froebrich 2012; Lee et al. 2012; Teixeira et al. 2012), and Vulpecula and Sagitarrius (Lee et al. 2012). (Winter 2011-2012) |
| NEWS: | Overview plots are now available for some of the busier regions (e.g. AFGL 961 in Monoceros, OMC-1/2/3 in Orion A, NGC 1333 in Perseus, etc.). See the individual html tables for details. |
For a number of years, astronomers have been imaging Herbig-Haro (HH) objects, jets and outflows in star forming regions in the near-infrared. The molecular hydrogen v=1-0S(1) line at 2.122 micron is a particularly powerful tracer of shock-excited features in molecular outflows. Although excited in a similar way to HH objects, these molecular hydrogen emission-line features are often too deeply embedded to be seen at optical wavelengths. They are thus not classified as HH objects, and are instead labeled in a rather hap-hazard way, often with the authors' initials. In large databases like Simbad this can lead to some ambiguity.
Our goal with this catalogue is therefore to develop a self-consistent list of Molecular Hydrogen emission-line Objects (MHOs). With guidance from the IAU Working Group on Designations we have adopted a scheme that simply lists objects sequentially, although objects are grouped by region (see below). The acronym "MHO" has been approved by the IAU registry, and has been entered into the on-line Reference Dictionary of Nomenclature of Celestial Objects. We use this acronym for all objects in the catalogue (and please note the space between the acronym and the number, e.g. MHO 1, MHO 99, etc.).
Only objects associated with outflows from young stars (Young Stellar Objects and protostars) are included in this catalogue. We do not list outflows from evolved stars (AGB stars or Proto-Planetary Nebulae) or extra-galactic sources. Also, objects should be spatially resolved; unresolved emission-line regions associated with an accretion disk or the base of an outflow (that were observed spectroscopically) are not listed.
Since large-scale imaging surveys are now revealing hundreds of objects in some regions, spectroscopic confirmation of every feature is not practical. However, narrow-band molecular hydrogen images must be accompanied with either adjacent narrow-band continuum images or (scaled) broad-band images, so that MHOs may be distinguished from wisps and knots of continuum emission. Morphology alone should not be used to identify MHOs, although an objects "shape" may be used to distinguish features in outflows from fluorescently excited nebulae. If available, MHOs should also have a spectrum consistent with thermal (shock) excitation, rather than non-thermal (fluorescent) excitation.
MHOs should be identified in the near-infrared (1-2.5 micron) lines of molecular hydrogen. Objects detected only in other near-IR lines (e.g. [FeII]) are not included. At the present time we are also excluding objects observed only in the UV or mid-infrared (e.g. with the Spitzer Space Telescope). Obviously, if an object is subsequently detected in molecular hydrogen emission in the near-IR, it should be included in the MHO catalogue.
WHEREVER POSSIBLE, WHOLE OUTFLOWS SHOULD BE GIVEN A SINGLE MHO NUMBER. In some cases the two lobes of a bipolar outflow could be given two consecutive numbers, as is sometimes the case with HH objects (e.g. HH 1/2). If it is not clear that widely-spaced objects are associated with the same outflow, separate MHO numbers could be given to each feature; MHO 187-189, shown below, is such an example. Multiple compact knots within the same outflow should not be given separate MHO numbers. Instead, if labeling these sub-features is desirable, letters should be used; if further granularity is needed, sub-knots should be labeled with letters and numbers. Detailed studies of many HH objects have used this scheme: HH 2, for example, is split into HH 2A, HH 2B, HH 2C, etc.; some authors have devided these knots further, into sub-knots HH 2A1, HH 2A2, etc.
For examples of MHO labeling, see the overview plots of NGC 2264-IRS2 in Monoceros , OMC-1 in Orion A , and, for a particularly complex region, AFGL 961 .
Finally, for completeness we have also given a catalogue number to many well-know HH objects (e.g. HH 1/2 = MHO 120/125, HH 212 = MHO 499), though only if these are detected in the near-IR lines of H2. Whenever possible, we group features together in a manner consistent with the HH object catalogue.
So how do I add new molecular hydrogen emission-line objects to the catalogue? Our aim is to keep the catalogue of MHOs as up-to-date as possible. Also, obviously we want to avoid duplication of catalogue numbers (people using the same numbers for different objects). Therefore, we ask that those with new discoveries please contact Chris Davis (c.j.davis@nasa.gov) before papers are written, and certainly before figures and tables of MHOs are finalized, so that new numbers can be assigned.
Click on the links below to access tables of MHOs, grouped by region. Coordinates and images of individual objects are presented, together with references to discovery and other imaging papers, designations or names used in the literature, and the numbers of associated HH objects. Please note that the tables do not contain a complete list of all papers written on a given object; only near-IR imaging papers are included. However, amendments and additions are certainly welcome; please contact Chris Davis at c.j.davis@nasa.gov.
| Region | Map | Approx. RA Range | Approx. Dec Range | MHO # | .txt |
|---|---|---|---|---|---|
| Perseus | M2 | 03h 00m → 04h 00m | +25o → +35o | 500-699 | Per.txt |
| Auriga (excl. Per/Gem) | M2 | 03h 30m → 06h 30m | +30o → +56o | 1000-1099 | Aur.txt |
| Taurus (excl. Ori/Per) | M2 | 03h 00m → 05h 50m | +10o → +30o | 700-799 | Tau.txt |
| Camelopardalis | M1 | 04h 00m → 08h 00m | +56o → +90o | 1100-1199 | Cam.txt |
| Orion A | M3 | 04h 45m → 06h 00m | -15o → -04o | 1-299 | OriA.txt |
| Orion B (excl. Tau) | M3 | 04h 45m → 06h 00m | -04o → +16o | 300-499 | OriB.txt |
| Gemini | M3 | 05h 50m → 08h 00m | +14o → + 34o | 1200-1299 | Gem.txt |
| Monoceros | M3 | 06h 00m → 08h 30m | -13o → +14o | 1300-1399, 3100-3199 | Mon.txt |
| Puppis (excl. Vela) | M4 | 06h 30m → 09h 00m | -52o → -13o | 1400-1499 | Pup.txt |
| Vela | M4 | 07h 30m → 11h 00m | -55o → -38o | 1500-1599 | Vel.txt |
| Carina | M5 | 08h 00m → 12h 00m | -75o → -55o | 1600-1699 | Car.txt |
| Chameleon (excl. Car) | M5 | 08h 00m → 14h 00m | -85o → -70o | 3000-3099 | Cha.txt |
| Centaurus | M5 | 12h 00m → 15h 00m | -70o → -30o | 1700-1799 | Cen.txt |
| Circinus/Lupus | M6 | 15h 00m → 16h 00m | -70o → -30o | 1800-1899 | CirLup.txt |
| Scorpius | M6 | 16h 00m → 18h 00m | -60o → -30o | 1900-1999 | Sco.txt |
| Corona Australis | M6 | 18h 00m → 19h 30m | -45o → -35o | 2000-2099 | CrA.txt |
| Ophiuchus (excl. Ser) | M6 | 16h 00m → 18h 00m | -30o → +05o | 2100-2199 | Oph.txt |
| Serpens | M7 | 17h 30m → 18h 40m | -15o → +05o | 2200-2299, 3200-3299 |
Ser.txt |
| Sagittarius (excl. Ser) | M7 | 18h 00m → 20h 30m | -35o → -12o | 2300-2399 | Sgr.txt |
| Aquila (excl. Lyr) | M7 | 18h 40m → 20h 30m | -12o → +15o | 2400-2499 | Aqu.txt |
| Lyra | M8 | 18h 20m → 19h 00m | +5o → +45o | 2500-2599 | Lyr.txt |
| Vulpecula | M8 | 19h 00m → 21h 30m | +15o → +30o | 2600-2699 | Vul.txt |
| Cygnus | M9 | 19h 00m → 22h 00m | +30o → +55o | 800-999 | Cyg.txt |
| Cepheus (excl. Cas) | M9 | 19h 00m → 23h 30m | +55o → +90o | 2700-2799 | Cep.txt |
| Andromeda | M9 | 22h 00m → 00h 00m | +30o → +55o | 2800-2899 | And.txt |
| Cassiopeia (excl. Cep) | M1 | 23h 00m → 04h 00m | +50o → +90o | 2900-2999 | Cas.txt |
| Bibliography | |||||
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Currently there are 1280 entries in the MHO catalogue
(Last update: 31 January 2012) |
Links in the first column (and on the side-bar) are to html tables; in the final column we present the same tables (abbreviated) in ascii format. If a link is not active, there are no known MHOs in that region. Please note - some of the larger html tables (Perseus, Orion A, etc.) may be slow to load; if you are having difficulty, please try one of the smaller tables (Carina or Sagittarius) first.
Since there are no official names for, or boundaries to, the star-forming molecular clouds in our galaxy, the regions listed above are loosely based on the 88 constellations (which have strict boundaries defined by the IAU) and large-scale molecular line surveys. Moreover, in the heavily-populated area of Orion, we have split the region up into two sub-regions, Orion A and Orion B, again using low-resolution maps of the associated molecular clouds as a guide.
The boundaries of each region are marked on low-resolution CO J=1-0 maps, M1-M9, in the second column in the above table (or see this PDF file of all regions); the approximate RA and Dec ranges of the regions are listed in the third and fourth columns. Note that not all constellations are listed above, since some do not contain star forming regions and/or known outflows with MHOs.
A simple ascii text table listing MHO#, Right Ascension, Declination, associated HH object, and region, for all MHOs (from all regions) can be found here: masterText.txt
Search the catalogue for objects within a given area using this tool:
MHO Search
If you wish to acknowledge this web-site, please note that the "MHO catalogue is hosted by the Joint Astronomy Centre in Hawaii". A PAPER describing the catalogue and presenting the first ~1000 objects has also been published in A&A (Davis et al. 2010, A&A, 511, A24). However, note that the tables in the appendix of this paper will become progressively more incomplete as new objects are added to the on-line catalogue.
We thank the "Clearing House" of the Commission 5 Working Group on Designations, particularly the chair, Marion Schmitz, for their guidance, and the star formation community, especially Bo Reipurth, for their valuable input. This project would not have been possible without support from the Joint Astronomy Centre.
Website created by Ryan Gell and maintained by Chris Davis