13 research outputs found
GASKAP-HI pilot survey science I: ASKAP zoom observations of Hi emission in the Small Magellanic Cloud
We present the most sensitive and detailed view of the neutral hydrogen (HI) emission associated with the Small Magellanic Cloud (SMC), through the combination of data from the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot observations, for the first time, reveal HI in the SMC on similar physical scales as other important tracers of the interstellar medium, such as molecular gas and dust. The resultant image cube possesses an rms noise level of 1.1K (1.6 mJy beam(-1)) per 0.98 km s(-1) spectral channel with an angular resolution of 30" (similar to 10 pc). We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire similar to 25 deg(2) field-of-view. We provide an overview of the data products and characterise several aspects including the noise properties as a function of angular resolution and the represented spatial scales by deriving the global transfer function over the full spectral range. A preliminary spatial power spectrum analysis on individual spectral channels reveals that the power law nature of the density distribution extends down to scales of 10 pc. We highlight the scientific potential of these data by comparing the properties of an outflowing high-velocity cloud with previous ASKAP+Parkes HI test observations
MIGHTEE-H I: the baryonic Tully–Fisher relation over the last billion years
Using a sample of 67 galaxies from the MeerKAT International GigaHertz Tiered Extragalactic Exploration Survey Early Science data, we study the H i-based baryonic Tully-Fisher relation (bTFr), covering a period of ∼1 billion years (0 ≤ z ≤ 0.081). We consider the bTFr based on two different rotational velocity measures: The width of the global H i profile and Vout, measured as the outermost rotational velocity from the resolved H i rotation curves. Both relations exhibit very low intrinsic scatter orthogonal to the best-fitting relation (σ⊥ = 0.07 ± 0.01), comparable to the SPARC sample at z 0. The slopes of the relations are similar and consistent with the z 0 studies (3.66+0.35-0.29 for W50 and 3.47+0.37-0.30 for Vout). We find no evidence that the bTFr has evolved over the last billion years, and all galaxies in our sample are consistent with the same relation independent of redshift and the rotational velocity measure. Our results set-up a reference for all future studies of the H i-based bTFr as a function of redshift that will be conducted with the ongoing deep SKA pathfinders surveys
Mind Map Our Way into Effective Student Questioning: a Principle-Based Scenario
Student questioning is an important self-regulative strategy and has multiple benefits
for teaching and learning science. Teachers, however, need support to align student
questioning to curricular goals. This study tests a prototype of a principle-based scenario that
supports teachers in guiding effective student questioning. In the scenario, mind mapping is
used to provide both curricular structure as well as support for student questioning. The fidelity
of structure and the process of implementation were verified by interviews, video data and a
product collection. Results show that the scenario was relevant for teachers, practical in use
and effective for guiding student questioning. Results also suggest that shared responsibility
for classroom mind maps contributed to more intensive collective knowledge construction
GASKAP-HI pilot survey science I: ASKAP zoom observations of Hi emission in the Small Magellanic Cloud
We present the most sensitive and detailed view of the neutral hydrogen emission associated with the Small Magellanic Cloud (SMC), through the combination of data from the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot observations, for the first time, reveal in the SMC on similar physical scales as other important tracers of the interstellar medium, such as molecular gas and dust. The resultant image cube possesses an rms noise level of 1.1 K spectral channel with an angular resolution of . We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire field-of-view. We provide an overview of the data products and characterise several aspects including the noise properties as a function of angular resolution and the represented spatial scales by deriving the global transfer function over the full spectral range. A preliminary spatial power spectrum analysis on individual spectral channels reveals that the power law nature of the density distribution extends down to scales of 10 pc. We highlight the scientific potential of these data by comparing the properties of an outflowing high-velocity cloud with previous ASKAP+Parkes test observations