Infrared Extinction toward Nearby Star-forming Regions

By Kevin Flaherty, J. Pipher, S. Megeath, E. Winston, R. Gutermuth, J. Muzerolle, L. Allen, G. Fazio. 2007

297 citations recorded by the source corpus.

We present an independent estimate of the interstellar extinction law for the Spitzer IRAC bands, as well as a first attempt at extending the law to the 24 μm MIPS band. The source data for these measurements are observations of five nearby star-forming regions: the Orion A cloud, NGC 2068/2071, NGC 2024/2023, Serpens, and Ophiuchus. Color excess ratios E/E were measured for stars without infrared excess dust emission from circumstellar disks/envelopes. For four of these five regions, the extinction laws are similar at all wavelengths and differ systematically from a previous determination of the extinction law, which was dominated by the diffuse ISM, derived for the IRAC bands. This difference could be due to the difference in the dust properties of the dense molecular clouds observed here and those of the diffuse ISM. The extinction law at longer wavelengths toward the Ophiuchus region lies between that to the other four regions studied here and that for the ISM. In addition, we extended our extinction law determination to 24 μm for Serpens and NGC 2068/2071 using Spitzer MIPS data. We compare these results against several ISO extinction law determinations, although in each case there are assumptions which make absolute comparison uncertain. However, our work confirms a relatively flatter extinction curve from 4 to 8 μm than the previously assumed standard, as noted by all of these recent studies. The extinction law at 24 μm is consistent with previous measurements and models, although there are relatively large uncertainties.

Subfields: Astronomy and Astrophysics, Spectroscopy

View Paper: https://www.semanticscholar.org/paper/e23118121bf10b3835b3fab08084482013a8bc53

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Citations in the corpus

Spitzer Observations of NGC 1333: A Study of Structure and Evolution in a Nearby Embedded Cluster (2007, methodology): “…utilized dereddened 2-8 µm SED slopes to demonstrate that one could separate protostars, stars with disks, and diskless photospheres quite effectively with the K − [3.6] vs. [3.6] − [4.5] color-color diagram, provided that the colors were dereddened via the reddening law of Flaherty et al. (2007).”
LINE DERIVED INFRARED EXTINCTION TOWARD THE GALACTIC CENTER (2011, background): “…et al. 2003; Whittet et al. 1997), while MIR-flattening is observed in many regions (Zasowski et al. 2009; Jiang et al. 2003, 2006; Gao et al. 2009; Flaherty et al. 2007; Román-Zúñiga et al. 2007; Nishiyama et al. 2009; Indebetouw et al. 2005) renders the idea that composite particles glued by…”
INTRINSICALLY RED SOURCES OBSERVED BY SPITZER IN THE GALACTIC MIDPLANE (2008, background): “The choice of IRAC 4.5µm (rather than 3.6µm) as the lower wavelength was motivated by recent results which suggest that the interstellar extinction law is approximately flat between 4.5µm and 8.0µm (Lutz 1999; Indebetouw et al. 2005; Flaherty et al. 2007).”
THE DISK POPULATION OF THE TAURUS STAR-FORMING REGION (2009, methodology): “We have reddened the photospheric SEDs by combining the extinction estimates described by Luhman et al. (2009b) with the reddening laws from Rieke & Lebofsky (1985) and Flaherty et al. (2007).”
STAR FORMATION IN THE CENTRAL 400 PC OF THE MILKY WAY: EVIDENCE FOR A POPULATION OF MASSIVE YOUNG STELLAR OBJECTS (2009, unknown): “Flaherty et al. (2007) have recently derived A(8µm) -”
THE MID-INFRARED EXTINCTION LAW IN THE OPHIUCHUS, PERSEUS, AND SERPENS MOLECULAR CLOUDS (2008, methodology): “Flaherty et al. (2007) also used Spitzer to measure the extinction law toward five regions.”
Peering through the veil: near-infrared photometry and extinction for the Galactic nuclear star cluster (2009, background): “We also confirm the flattening of the extinction law beyond ∼ 3 µm (see also Lutz et al. 1996; Indebetouw et al. 2005; Viehmann et al. 2005; Flaherty et al. 2007; Nishiyama et al. 2009).”
EXTENDING THE NEARBY GALAXY HERITAGE WITH WISE: FIRST RESULTS FROM THE WISE ENHANCED RESOLUTION GALAXY ATLAS (2012, methodology): “…have been corrected for the estimated foreground Galactic extinction, where we have adopted the following coef- ficients based on merging the Cardelli, Clayton, & Mathis (1990), Flaherty et al. (2007) and Indebetouw et al. (2005) relations for the near and mid-IR windows: AK = 0.114 AV ; A3.”
The Disk Population of the Chamaeleon I Star-forming Region (2008, methodology): “We have dereddened these slopes using the extinctions from Luhman (2007) and the reddening law from Flaherty et al. (2007), except for 10 members that lack spectral types and extinction estimates.”
THE SPITZER c2d LEGACY RESULTS: STAR-FORMATION RATES AND EFFICIENCIES; EVOLUTION AND LIFETIMES (2008, methodology): “We used the extinction law with RV = 5.5 (Weingartner & Draine 2001), which reproduces reasonably well the data for molecular clouds (Flaherty et al. 2007; Chapman et al. 2009), to determine AV .”
Clustered and Triggered Star Formation in W5: Observations with Spitzer (2008, methodology): “With AV values in hand for all sources, we deredden their IRAC magnitudes using the IR extinction law presented in Flaherty et al. (2007), assuming each source is seen behind the full extinguishing column in each case.”
SDC13 infrared dark clouds: longitudinally collapsing filaments? (2013, background): “One advantage provided by these two wavelengths is that they are similarly affected by extinction (Flaherty et al. 2007; Chapman et al. 2009), which implies that estimated values of α[8−24] are not much affected by extinction.”
POLARIZED FAR-INFRARED AND SUBMILLIMETER EMISSION FROM INTERSTELLAR DUST (2008, background): “8 µm, the extinction is somewhat controversial (Lutz et al. 1996; Rosenthal et al. 2000; Indebetouw et al. 2005; Flaherty et al. 2007), but the present study will be limited to the wavelength range 0.1 < λ < 2.65 µm, where the extinction by dust in diffuse regions appears to be securely known.”
TWO MICRON ALL SKY SURVEY PHOTOMETRIC REDSHIFT CATALOG: A COMPREHENSIVE THREE-DIMENSIONAL CENSUS OF THE WHOLE SKY (2013, methodology): “All the WISE W1 and W2 magnitudes were extinctioncorrected using coefficients according to Flaherty et al. (2007): AW1/EBV = 0.231 and AW2/EBV = 0.194.”
The UKIDSS galactic plane survey (2007, methodology): “Like Gutermuth, we use the extinction law of Flaherty et al.(2007) to determine the extinction in the mid-IR bandpasses, relative to the K band.”
THE PRESENT-DAY STAR FORMATION RATE OF THE MILKY WAY DETERMINED FROM SPITZER-DETECTED YOUNG STELLAR OBJECTS (2010, background): “In recent years there have been a number of determinations of the extinction law at mid- infrared wavelengths for both the interstellar medium (Lutz 1999; Indebetouw et al. 2005) and for star forming regions (Flaherty et al. 2007).”
THE SPITZER SPACE TELESCOPE SURVEY OF THE ORION A AND B MOLECULAR CLOUDS. I. A CENSUS OF DUSTY YOUNG STELLAR OBJECTS AND A STUDY OF THEIR MID-INFRARED VARIABILITY (2012, background): “First, the measured values of E(H −Ks)/E(Ks −J ) in Flaherty et al. (2007) and their adopted value of AH /AKs = 1.55 requires a value AJ /AKs = 2.65.”
A CORRELATION BETWEEN SURFACE DENSITIES OF YOUNG STELLAR OBJECTS AND GAS IN EIGHT NEARBY MOLECULAR CLOUDS (2011, methodology): “• Some clouds exhibit large deviations from the power law form apparent in MonR2 and Ophiuchus; we argue that these deviations are due to gas dispersal by massive stars and non-coevality in each cloud.”