2MASS wide field extinction maps. I. The Pipe nebula

By Marco Lombardi, Joao F. Alves, C. Lada. 2006

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Context. Aims. We present a $8^\circ\times6^\circ$, high resolution extinction map of the Pipe nebula using 4.5 million stars from the Two Micron All Sky Survey (2MASS) point source catalog. Methods. The use of Nicer (Lombardi & Alves 2001, A&A, 377, 1023), a robust and optimal technique to map the dust column density, allows us to detect a $A_{\rm V} = 0.5~\mbox{mag}$ extinction at a 3- σ level with a $1~\mbox{ arcmin}$ resolution. Results. ( i ) We find for the Pipe nebula a normal reddening law, $E(J - H) = (1.85 \pm 0.15) E(H - K)$. ( ii ) We measure the cloud distance using Hipparchos and Tycho parallaxes, and obtain $130^{+24}_{-58}~\mbox{ pc}$. This, together with the total estimated mass, $10^4~{M}_\odot$, makes the Pipe the closest massive cloud complex to Earth. ( iii ) We compare the Nicer extinction map to the NANTEN ${}^{12}$CO observations and derive with unprecedented accuracy the relationship between the near-infrared extinction and the 12 CO column density and hence (indirectly) the 12 CO X-factor, that we estimate to be $2.91 \times 10^{20}~\mbox{cm}^{-2}\,\mbox{K}^{-1}\,\mbox{km}^{-1}\,\mbox{s}$ in the range $A_{\rm V} \in [0.9, 5.4]~\mbox{mag}$. ( iv ) We identify approximately 1500 OH/IR stars located within the Galactic bulge in the direction of the Pipe field. This represents a significant increase of the known numbers of such stars in the Galaxy. Conclusions. Our analysis confirms the power and simplicity of the color excess technique to study molecular clouds. The comparison with the NANTEN ${}^{12}$CO data corroborates the insensitivity of CO observations to low column densities (up to approximately $2~\mbox{mag}$ in A V ), and shows also an irreducible uncertainty in the dust-CO correlation of about $1~\mbox{mag}$ of visual extinction.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/61f268743992c3eaa9c4a42c459034449f720597

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Citations in the corpus

WHAT DETERMINES THE DENSITY STRUCTURE OF MOLECULAR CLOUDS? A CASE STUDY OF ORION B WITH HERSCHEL (2013, methodology): “…(2010)) and SPIRE (Griffin et al. (2010)) data provides column density maps that are superior to those obtained from extinction using near-IR data (Lombardi et al. (2006), Kainulainen et al. (2009), Froebrich & Rowles (2010), Schneider et al. (2011)) that have angular resolutions of ≈2′ and…”
THE STAR FORMATION RATE AND GAS SURFACE DENSITY RELATION IN THE MILKY WAY: IMPLICATIONS FOR EXTRAGALACTIC STUDIES (2010, background): “…(Frerking et al. 1982), extinction maps from optical star counts (Duvert et al. 1986; Bachiller & Cernicharo 1986; Langer et al. 1989) and 2MASS data (Lombardi et al. 2006; Pineda et al. 2008), and theoretically by the assumption that giant molecular clouds are in gravitational equilibrium…”
Modelling CO emission – I. CO as a column density tracer and the X factor in molecular clouds (2010, background): “Indeed, saturation at high CO intensities has been observed in MCs in the solar neighborhood (e.g. Lombardi et al. 2006; Pineda et al. 2008).”
Star and Protoplanetary Disk Properties in Orion's Suburbs (2009, background): “Rather than the dense regions, which are known to show strong density enhancements on small scales (e.g. Lombardi et al. 2006), we trace the low density regions that surround the cores.”
FILAMENTARY STRUCTURE OF STAR-FORMING COMPLEXES (2009, background): “Figure 3 shows an AK extinction image of Barnard 59, the most prominent part of the Pipe nebula (Lombardi et al 2006).”
Infrared Extinction toward Nearby Star-forming Regions (2007, background): “The availability of 2MASS has allowed for construction of large scale extincton maps in the near-infrared which trace a substantial range in column densities (Lada et al. 2007; Lombardi et al. 2006).”
ON THE STAR FORMATION RATES IN MOLECULAR CLOUDS (2010, methodology): “For example, consider two of the nearest molecular clouds to the sun, the Ophiuchus cloud at 120 pc and the Pipe Nebula at 130 pc.”
A THREE-DIMENSIONAL MAP OF MILKY WAY DUST (2015, background): “Lombardi & Alves (2001, NICER) and Lombardi (2009, NICEST) extended on this algorithm, which has now been applied to 2MASS photometry to obtain reddening maps of a host of cloud complexes (Lombardi et al. 2006, 2008, 2010, 2011; Alves et al. 2014).”
Probing the evolution of molecular cloud structure: From quiescence to birth (2009, methodology): “F r example, Lombardi et al. (2006, 2008a) examined the column density PDFs in the Pipe, Rho Oph, and Lupus molecular clouds.”
The mass function of dense molecular cores and the origin of the IMF (2006, methodology): “W used data from the recent wide-field extinction map of the Pipe Nebula constructed by Lombardi et al. (2006), hereafter LAL06, using 2MASS data.”
CO Isotopologues in the Perseus Molecular Cloud Complex: the X-factor and Regional Variations (2008, methodology): “However, the factor derived by Lombardi et al. (2006) includes a correction for helium and uses the nonstandard expression N (H) ¼ N (H i)þ N (H2), while using the standard definition of N (H) ¼ N (H i)þ 2N (H2) they would derive (1:06 0:02) ; 1020 cm 2 K 1 km 1 s. Frerking et al. (1982) studied…”
Comparing the statistics of interstellar turbulence in simulations and observations - Solenoidal versus compressive turbulence forcing (2009, methodology): “For instance, Lombardi et al. (2006) had to apply combinations of multiple Gaussian distributions to obtain good agreement with the measured PDF data.”
Hipparcos distance estimates of the Ophiuchus and the Lupus cloud complexes (2008, methodology): “Following Lombardi et al. (2006), we assumed that the AV measurement for foreground stars is small, while a fraction f of the background stars is distributed as a normal variable with relative large mean and variance.”
THE PdBI ARCSECOND WHIRLPOOL SURVEY (PAWS). I. A CLOUD-SCALE/MULTI-WAVELENGTH VIEW OF THE INTERSTELLAR MEDIUM IN A GRAND-DESIGN SPIRAL GALAXY (2013, background): “…measures of AV from individual stars with NIR colors typically find that the 12CO(1-0) emission has an almost linear relation to AV for 2mag ≤ AV ≤ (4−6) mag while for large extinction values the 12CO emission appears to saturate (Lombardi et al. 2006; Pineda et al. 2008; Heiderman et al. 2010).”
LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER (2011, background): “For most molecular clouds, the extinction is, with α ≈ −1.8 (Román-Zúñiga et al. 2007; Naoi et al. 2006; Kenyon et al. 1998; Flaherty et al. 2007; Lombardi et al. 2006), flatter than for the Galactic disk sight lines.”